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The definitive remapping thread

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The definitive VR6 & R32 Remapping thread




Little bit of a “Bosch recalibration” thread for ya as I wasn't the op on the other one and have spent a while putting my notes into some legible format. About 90% of what I have done over the past half decade is predominantly ME7.1.1. based, or, as a conservative estimate, around 5000+ hrs at least solely on the V6/R32 ecu's. As such, it is somewhat bias to that – however, the older Motronic don't have the central torque structure but are similar and I explain the evolutions! Plenty of info either way – hope it serves you well, did what I can!



1. Any work undertaken is at your own risk, I accept no responsibility for any damage or costs that may arise, yadda, yadda ........ you know the sketch, don't come crying to me!

2. The information herein is pretty much as accurate as you can get in a forum thread. I have, however, written a lot of things off the top of my head and usually between the hours of midnight and 3a.m. so point out anything I may have not written correctly, I am fallible after all! Other parts are my notes on Bosch specifics over the years, taken from a number of documents that have been on the net for years or are excerpts directly from Bosch's info due to the fact that I am unable to make them any simpler (ME7 tech esp.). I have e-mailed Bosch several times on this so we should be good IP Rights wise, but any operating under the Legal Services Act should e-mail me directly if any probs!

3. Unless otherwise stated herein, all screenshots are my own work/files I have built over the years so all good there too!


So, without further ado then, a bit of info on the common phrase “remapping” or (Bosch recalibration, which means detailed systems learning as opposed to simply remapping or tweaking a few maps)!


Remapping” is a generic term many of you would have heard, “get an extra 25hp and 20lb/ft with our Stage 1 remap!” being the most common reasons for remapping or perhaps fuel economy for fleet vehicles or business users, for example.


But what exactly is remapping?


Remapping is a generic term that essentially means; “the recalibration of electronic systems to meet desired demands”. The most common demands are of course, an increase in power and torque, often allied to increased economy from your vehicle.


How is this possible?


In short, your computer, nowadays be that the Engine Control Unit (ECU – sometimes referred to as the Engine Control Module – ECM in Bosch circles, in case I switch hereafter), or one of a number of electronic control systems on the modern vehicles, has it's data modified, usually for optimization in line with a specific function or purpose.


How is this done?


Certain equipment is used to get a “read” of the data that the ecu contains, a binary file (.bin or simply bin hereafter), which is then placed into a converter (calibration software), which turns it into hexidecimal information. This “hex” file is then broken down or reverse engineered to turn it into specific maps or functions of that particular ecu - “defining it's control systems”.


Unless you can directly read hex files (you do pick this up by the way), a structured layout of the ecu is needed so you know what part of it is used to control what systems (for example the lambda probes or injectors) and then subsequently “recalibrate” them for what is desired.


In terms of “the trade” - there are generally 2 main ways this is done;

Most garages, simply due to equipment costs (like a dyno or the calibration software or both), tend to use “re-seller” files. What generally happens here is they take a read of your ecu, then send the file, the stock bin, to their calibration company (usually a named brand that has covered a number of conventional tunes on a particular group of vehicles or ecu makes), before receiving the “tuned” version of the file back to upload it to your car. Et voila – a remapped car! In fact certain companies are now offering the option of owners to use their own cables and flashing it yourself, thus cutting out the middle man!

The second way is what these “calibrators” do and what we look at in here in more detail and in terms of DIY tuning. How good a “calibrator” is and to what extent they modify the data can vary massively. All that is generally needed for a basic remap of your car is the defining and modification of as little as half a dozen maps – tweaking a few data cells within them to achieve

the desired results. However a good calibrator will learn the entire systems, the intricate details and take many years perfecting their techniques.


There can also be variations of the two and how data is modified can vary depending on the equipment and resources any garage has as well as the ecu age/revision.


What about DIY?

Well, that is the same as professional in many respects, the extent to which you build and modify your data or educate yourself on these things is entirely up to you. You can simply pick out the main tuning maps to remap your car or you can continue to learn what is detailed within the thread!


Why re-calibrate your ecu?

The data within your ecu is simply not optimal for a huge number of reasons. Emissions and legislative aspects, marketing (i.e. “the new “200ps” Golf GTI”) in accordance with often de-tuning for longevity purposes, quality of fuel and the addition or deleting of parts to name but a few. Due to these many reasons, the data usually is ripe for re-calibrating for optimization.


On to DIY tuning then!

Edited by RBPE
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DIY Tuning:

DIY tuning certainly doesn't mean that it can't be done well, even better than many professional tunes, as many free resources are available nowadays, but the fact of the matter is, in order for it to be good, do your homework first and take time and care and you should be fine!

How can I protect my car from damage?

Before anything, make sure all the systems are in good working order, spark plugs or coils, injectors and fuel pump and so on. Secondly make sure that there is plenty of fuel, you'll be often working the engine hard at times and as such, you want to avoid anything like fuel starvation under heavy loads.
Once your car is ready for tuning the main points are being able to accurately measure data as quickly as possible in order to avoid potentially devastating detonation and subsequently making the changes.  Monitoring what you are doing and your changes, is known as “datalogging” and “emulation” and the main difference in terms of DIY v's Professional costs can be had here. 


In order for a professional calibrator to operate on a number of different vehicles, some transferable real time a/f measuring equipment is often needed, so a system has to be devised that can be set up, removed and transferred between numerous vehicles, so they don't have to weld in bungs for wideband equipment on every single car. A dyno/rolling road is also a wise investment as it means they don't have to take cars out on the road all the time, insurance costs and all the other downsides.

For DIY, we have to make do with what resources we have to hand then, instead of a rolling road we have to “roll it on the road” and instead of expensive data logging and transferable equipment we need to concentrate on a decent set up on our own vehicles as best our budgets allow! It is ALWAYS recommended that if you are going the DIY route then invest in a wideband monitor system from the likes of AEM or Innovate, the best way you can monitor your air/fuel ratio in real time. The difference here is that you will often weld in a bung which like I said, is not something those who map half a dozen cars plus a day can do realistically!

*** Really do think about using a wideband monitoring system like above if doing any of this, best way to ensure safe driving conditions when you make changes! ***

“Reading and Writing”:

Reading the data and writing it back on to the ecu can be done in a number of ways and this can depend on your ecu's/the processors within then. “Chipping” or removal of chips was something of a necessity on older Motronic variations whereas the modern ones like your ME7 ecu's tend to be flashed either directly over the OBD port or bench flashing may be necessary. 

In order to save the thread from getting too convoluted, I'll direct you to some forums/threads to see what has been used or what seems to work best for your particular application. There are both evolutionary aspects of the Motronic and also the processor's within one specific Motronic system which seem to make a difference in this area,  bench flashing seems to be be preferred with the newer ME7 V/R models although some cheap cables have been used as well as expensive and older Motronics tend to need “chipping” but can depend on evolution (more later).


ME7.1.1./R32 Bootmode DIY;



Logging & Emulation:

So, at this point we know that you need to read the data, make changes and upload. 
After that you need to log the data, make notes and changes accordingly and then put it back on the ecu again. In terms of DIY tuning, this can be one area that costs more than the others. The main part to note here is the time it takes to perfect a tune – reading, changing and writing the data each time you make a small change can mean that it takes a long time to do even tiny changes. Don't get mme wrong you can do this on stringent budgets, but I would look at making this area easier.

“Logging” and “Emulation” are aspects of being able to simulate data in real time or checking the data from your changes and the quicker you can do this, the better! In short, you can take a long time reading the data, making changes, uploading then checking the logs, making further tweaks and putting it back on again and again– certain set ups can be had that seriously cut down the time it takes to do this!
Some good power control is needed for emulation and the whole emulation/data logging set up can eventually cost as much as an expensive custom map depending on what equipment you use,  but it can be done so you can use it on numerous vehicles with relatively minor changes like connections, or it can pay dividends for things like turbo tunes as you upgrade the turbo, injectors and keep upping the boost for larger power increases than your average tune...... plus, you can tweak the data to your heart's content if you're never truly satisfied with what you've done (for any who have had a map think about the pedal feel or if that turbo remap boost came on a bit strong and you prefer a more linear feel for example and the cost of having your car mapped again or just putting up with it – unnecessary if you can do it yourself so pays for itself in the end!).

Please note that although the ME7 logger has been used many times on numerous ME7 equipped vehicles, it seems to be temperamental with the ME7.1.1. ecu's as found on your V6/R32 with the Siemens C167/ST10 processors. Emulation with things like a Moates set up seem preferred and are popular with my Moates suppliers for the JDM market although the ME7 set-ups are somewhat being evolved (see links below).  Any group buy thoughts let's see what we can do! Many VR6 12V owners tend to use Tunerpro and associating logging with numerous .xdf (tunerpro definition files) being available on their website so a nice free system there assuming you can put it on the ecu!
 We can possibly go into detail on these things at a later date.





So – you now have a good idea as to how to go about reading and writing and some set ups that help in being able to check and change the data quickly if need be..........

It's now on to making the tune!


In order to actually make a tune, you need to know what the data is that you have just read! You do this by placing it into a program that turns it into hexidecimal values and then you either;
1) learn the patterns associated with a particular file; for example, rpm's are used for a number of maps and they can also be the same data values as on other revisions of the same ecu and often in the same or similar blocks or areas – after some time this data or these common points become noticeable as you see the patterns over and over again). Few tuners will ever develop their skills enough to do this and you are getting deep into the reverse engineering and computer code writing aspects which many in the trade simply do not have the time to at least learn for their day to day work. There are a few winols vids on youtube showing this though if I remember right.
2) The most common method is to use a map pack file or definition file – DAMOS, .xdf and .ols being the most widely cited ones. Ideally you want one which is EXACTLY the same as your ecu revision, but more often than not you may have to settle with the same type of ecu but not quite the same revision. Due to this, the offsets (not lining up exactly when comparing 1 ecu to another), can vary and care and attention needs to made if making your own file, taking time to go over it all to see if it looks correctly laid out (many pro tunes can be all over the shop here, I suppose time and equipment make the differences). The slight offsets make the map definition go out of sync!


Although something less of a problem in the trade as many tuners share files using that particular software – i.e. offering a Stage 1 map for R32's using winols, they tend to be developed well whereas you may buy a pack from ebay or the like and who knows what's in them! 


How to start/practice and what programs to use?

Tunerpro seems to be the most popular free tuning software DIYers use, youtube vid link above somewhere, with numerous VR6 12V .xdf (their def file extensions) files being developed and even available for free on their website;


Fantastic bit of open source tuning if you ask me, well worth a donation!

VR6 .XDF Files on Tunerpro:


HXD is another free hex tool that has been used for Motronic tuning;


**** IMPORTANT NOTE: The main differences with the free hex software compared with the expensive ones tends to be the fact that you are likely going to have to manually change the checksums once you have made changes to the ecu. There is a link below that explains a bit of information on how to go about this and was done using the above hex programme. You will, however, have to sign up and make a few posts to get it but you will have to learn it if you use any program that needs manual checksum changes! Not sure if I can send it you directly but if any probs let me know. ****



Winols is an expensive hex tool that the top professionals use but can get very, very expensive (£10k's) and their demo version is exactly the same in structure. Their demo version is free but the downside is that you cannot export your file (write your changes onto a file to use), however it's layout is often easier to learn from than the free ones advertised so makes it easier to look at the data within the ecu.

Again you may have to sign up to Nefmoto and make some posts in order to get the ols files on there or look further into information on the forum but here is an easy way to learn about the ME7 contents and good practice using the winols demo.

Winols demo:


For your V6/R32 or simply learn for the VR6 or any other vehicles, there are some winols definition files here – there are also other ols files throughout the site to learn from within that “definition files” area;


*** One of the best ways to learn the ME7 ecu quickly and for free is to get one of the above ols files, put it into the winols demo and then go on Google translate and translate all the German to English. You will begin to pick up on common words used and then Google them to see what they mean, but they are essentially various electronics operations – detailed further below.

I would estimate it would take you something like 20 hours to convert it all or one of the many other ols files nearer your particular vehicle of Nefmoto, but should give you a good understanding quickly on the layouts of the entire ecu's within a couple of days or even a day of doing that!

With it you can look at the bigger 3D maps (big maps on def files have KF in them for “kennfelder” or map in German so look for them) or the actual hex data patterns are somewhat easier to see plus you can line files up and compare them if they have the same or similar maps or functions.

For a long weekend it is quite a good way to practice using such software and getting to know your/the ecu contents! ***


So – we now know about what happens with mapping, a wide range of cheap or free ways to go about it, the various things to take into account – it's now on to the Motronic technicalities!

Edited by RBPE
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Ignition – Motronic:
Takes approx. 2ms (0.002s) from start of mixture ignition to complete combustion.
Time remains constant for all engine speeds, time “available” for process to occur lessens as revs rise, therefore the spark must be generated sooner, this process is called ignition advance. 
At idle spark occurs near top of compression stoke, higher revs spark must be generated sooner so maximum cylinder pressure occurs on power stroke. 

Emissions system:
Throttle positioners and dashpots
Oxidation Cat
Secondary air system
Intake air pre-heating
Evaporative emissions (fuel tank)
Crankcase emissions

Leak Detection Pump (LDP) – pressurize evap system for emissions

Component control via ECU:

Example: Temp sensor receives constant 5V signal, also ground for accurate signal. As temp changes, resistance changes and results in variable voltage drop. ECU watches for a valid signal, which varies by component but will not be 0 or 5V. If battery+ Ground or 5V reference is seen by ecu, a DTC (Diagnostic Trouble Code) is seen.

Short circuit to Ground the same way – abnormal condition – DTC's, same applies for open circuit – i.e. no signal from loom/sensor etc – 0V – DTC.
ETC/DTC – Diagnostic/error trouble codes

Motronic 2.3.2 Basics:

ECU load and speed dependent.
Crank speed signal – secondary signal for crank position also
Hall sender in Dizzy provides camshaft position info to identify cylinder 1, allowing sequential injection and valve open time. 
Engine load from MAF.
02 sensor to check exhaust gasses/emissions/content – determines whether the injector open time needs to be lengthened or shortened for lambda=1 -  “Adaption”.
Values obtained from engine operating conditions are stored and used on next start up. These values can constantly change and the ecu learns from them - “adaptive learning”.

As well as mixture adaption, idle speed and ignition timing also adapt based on operating conditions.


Sequential fuel injection:
Fuel injection via map control
Starting enrichment
Ignition control
After-start enrichment
Acceleration enrichment
Fuel deceleration shut-off
Max engine speed
02 sensor control
Vehicle speed limits

Ignition timing control:
Dwell angle map control
starting control
Temp corrections
Digital Idle stabilization
Selective cylinder knock control

Idle air control (IAC):
Idle air volume via map control
Start control
Correction for A/C on 
Correction for transmission in gear

Exhaust Gas Recirculation Control:
EGR via map control
OBD Diagnostics (later models/legislative requirements at time)

Fuel tank ventilation:
FTV via map control


Adaption split into 2 areas – coarse and fine – the latter giving tighter control.
Coarse control range is known as long term adaption – a learned value.
Fine control range is known as short term adaption.
Fuel adaption is for part throttle and idle conditions.

Idle adaption = additive
Part throttle adaption = multiplicative



The period when the 02 sensor is not up to temp, therefore not used, is “open loop” operation, once a signal is used it becomes “closed loop”. As a result of the signal the ecu either lengthens the injector duration to richen the mixture or shortens it to lean it out. 
If sensor malfunctions, no signal and no substitute for it either, then ecu will revert to basic injection times so engine can run.
OBD MIL – No 02 signal within 5 minutes after engine start with coolant over 40C – also recognizes open and short circuits.

Placed in coolant stream, as coolant temp changes, resistance does and gives ecu guide to temperature.
Correction factor for ignition timing, injector duration and idle speed stabilizing. 
Knock sensor function
Idle speed adaption
02 sensor operation
Fuel tank ventilation

Substitute function:
If broke, ecu uses 80C temp. as substitute. 
Set to 20C at engine start, 10C increases per minute until 80-85C limit reached under malfunction.

Placed in air stream in inlet manifold, resistance changes when air passes over it. Increased air temp = increased resistance, colder air temp = decreased resistance.

USED FOR: Idle stabilization and ignition timing.
Substitute function: ECU uses 20C value from memory.

Used for atmospheric pressure sensing – from 14.7psi at sea level to around 12.5 high altitudes. 
Located in E-Box in passenger footwell.

Used to control turbo boost pressure at high altitudes to stop turbo overspeeding. Signal also used for A/F ratio adjustment at engine start up in high altitude regions. 

Vaccum line attached to manifold and instead of measuring ambient pressure, provides ecu with boost pressure for regulation.

Takes a small amount of non combustible exhaust gas and vents it back to intake. Increased temp changes resistance and tells ecu EGR working for better Nox emissions and reduced combustion temps.

Battery voltage. Injectors cycle faster (decreased dead times) at higher voltages and other parts that change speeds with voltage need the ecu to make adjustments accordingly.
Air conditioner/anciliiaries – the systems which can drain the amount of torque due to being attached to pulley system and clutched ON must be factored into in tuning i.e. revs rising at idle due to A/C being on.
Vehicle speed sensor – max limit's, plus more modern systems electronically controlled driver aids like ESP etc.
Automatic Gear related functions – smoother transitions etc


Later Motronic systems added component and system monitors which enabled the ecu to check the plausibility of signals it receives by looking at various related components., for example engine coolant temp with IAT then if the signal/values are too out of sync after a period of time (learning routines), it delivers a DTC.

Emissions control also became more stringent towards the late 90's, as such, more control over such systems evolved, for example additional sensors pre/post Cat. 
Evolution also came from things like; heated windscreens, better/more complex instrument clusters and so on as well as the development of electronic driver aids. The dreaded MIL light being something you'll be well aware of and had a new operating mode for the new OBD2 procedures.

The Hot Film Mass airflow sensor (HFM) were evolved into a heated metallic film on a ceramic substrate compared with earlier wire versions, thus negating the need for a “burn-off” period cleaning the sensor after the engine is switched off.
Throttle position sensor used as substitute if broken.

It was also around this time when dizzy systems were replaced with coilpacks/single coils as the ignition control became more advanced and controllable.

Variable length inlet manifold tracts came into play around this time too and the change over barrel functions needed to be integrated into the ecu as well as any other sub systems.

There were also evolutions of things like the fuel pumps and evap cannisters/control depending on M5 system ages and vehicle dependent.

At this time (mid/late 90's) on the M5.9 systems the throttle valve control was new and had 3 input sensors and 1 actuator, replacing the earlier TPS and IAT sensors, which were housed on the side of the throttle body unit, or, to be more technical, the “Throttle Control Module” (TCM).

There was a new on/off switch relating to a Closed Throttle Position (CTP). This was used for idling purposes and switches to a common ground signal once the throttle valve moves.

The ecu recognizes circuit malfunctions now referred to as low and high inputs for OBD compliance and also uses the Mass Air Flow sensor (MAF) to check for a plausible throttle position signal. The sensor was also upgraded over earlier items and housed in a glass membrane so as to stop turbulent and reverse flow giving the ecu incorrect readings.

Various other components also evolved due to design and manufacturing evolutions such as above.

Variable camshaft geometry also evolved at this time, first with the inlet cam and later with both inlet and exhaust camshafts. Such cam controls required additional sensory inputs and outputs and again, can be related to other systems that the ecu looks at within it's logic.


So, as the Motronic systems evolved, the ME7 as found on your V6 4motion and R32 vehicles were the next major development from Bosch and those we will look at in greater detail later on.
Where these systems differ to earlier Motronic systems is that they use a centralised processor that houses all sub-systems required for engine operation, whereas earlier systems used a number of processing points.

The previous way of looking at the inputs and outputs was done away with and the system became a torque based system.

This system is continually monitoring and looks at both external inputs like driver demand, as well as internal like idle speed. The ecu interprets them as “torque demands” and controls the actuators to produce the required torque as requested.

The ME7 designates signals and co-ordinates torque demand along 2 pathways;
CHARGE AIR PATH – All charge influencing components such as throttle angle or wastegate actuation. Lot's need to be looked at here for going FI for example.
CRANKSHAFT SYNCHRONOUS PATH – Controls all operations occurring in line with the operating cycle of the engine, such as ignition and injector opening and duration.

The engine based path is suited to meeting short term torque demands whereas the air path is good for long term demands. The former usually has a torque reduction effect whereas the latter is primarily required for required torque increases.

The throttle (abbr. DK -drosselklappen in tuning you'll come across), was the new “fly by wire” which receives it's sensory inputs from the pedal box – ergo, “driver demand”electronically rather than directly via a cable.

Evolutionary changes:

Electronically controlled throttle 
Cruise control – no longer vacuum but ecu integrated/controlled
Upgraded/evolved sensors including integrating BARO into ECU.
Re-circulation valve

Charge Air Pressure Sensor:
Earlier Motronic (M5.9) controlled charge pressure via a map which used engine speed, throttle angle and MAF (load).
ME7 housed this in the intake tract between charge cooler and throttle module and operates via a 5V reference with the resistance variations referencing the Manifold Absolute Pressure (MAP).
Atmospheric pressure gives a signal of approx 2.5V and works from 0.14-4.88V to give a plausible signal.

If this sensor fails then the charge air pressure is controlled by a map defined by engine speed and load – power however, is reduced.

Recirc valve N249:
Older M systems was operated by inlet manifold vacuum with fully closed throttle to give full engine vacuum to operate the valve.
With the new electronic control, the valve may be held partially open for emissions purposes and is used to provide vacuum to the re-circ valve from a reservoir under the front wheel housing liner which in turn allows the ecu to better control the valve under throttle transitions. If it fails, then the operation is done by manifold vacuum.

EPC – Electronic Power Control light was also added as a seperate indicator light and engine load signals/sensors use this light.

Further sensor and monitoring evolutions also followed for the ever tightening emissions controls.

So – that's a brief look at how the Motronic systems have evolved from the Motronic 2 systems through to the ME7 which should cover the basics of either the 12V or 24V motors!

Which is yours? 
VR6 12V Models will likely be either M2.7 to M3.8 age/market dependant, some 5.9 evolutions & V6 4Motion/R32 are ME7.1.1.

Edited by RBPE
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Due to the system’s modularity, very different system configurations can be realized. For example systems with different sensors for cylinder charge determination (air mass or speed density), naturally aspirated or turbocharged engines, engines with or without EGR and engines with variable camshaft actuation are possible.

 The main system features are as follows:

• The engine torque management which controls all torque influencing actuators
• A/F ratio control with a central A/F manager, λ-pilot control, λ-closed loop control, or alternatively with a Nernst or universal λ-sensor and trim control
• Sequential, cylinder individual fuel injection.
• Ignition timing, including control of dwell angle and ignition angle.
• Cylinder individual knock control.
• Emission control functions for optimized emissions during cranking, start and after start which enable the realization of different catalyst warm-up strategies, using a lean mixture or a rich mixture including exhaust gas recirculation (EGR) and secondary air injection (SAI) control if necessary
• Canister purge control based on canister charge.
• Idle speed control.
• Diagnostic and monitoring functions:
• The system is comprised of the complete OBD II functionality to meet both MY ‘98 and future EOBD requirements. A torque-based monitoring systems supervises the throttle control under all operating conditions and reacts with the appropriate limphome functionality in case of a failure.
• To communicate with external systems, such as a transmission control system or a vehicle dynamic control system, torque demands can be received via a torque interface, realized via CAN. Therefore the EMS is able to process external torque demands within the torque manager. 
• Conventional or continuous camshaft control.
• Resonance flap actuation.
• Engine fan control.
• Control of air-conditioner (A/C).
• Cruise control.
• The system contains the necessary interfaces to application tools, end of line programming tools, service and SCAN-tools.
• Immobilizer.
• Additional customer defined functions as required.

In principal, the comprehensive dependency of internal torque on cylinder charge, engine speed, Lambda, ignition timing and cylinder individual fuel cut-off could be described in a five dimension map

The decisive step to simplify this dependency is the introduction of two central reference values:
• the optimal spark advance “sa_opt“ and
• the corresponding optimal internal torque “tqi_opt“, which reaches it’s maximum value at optimal spark advance.
In some operating points the optimal spark advance is a theoretical value, because of the engine knock limit.

Both reference values refer to Lambda equal to 1.0 („sa_opt_l1“ and „tqi_opt_l1“) and are defined by 2- dimensional look-up tables:
sa_opt_l1 = fn. (rc, n_eng) (1)
tqi_opt_l1 = fn. (rc, n_eng) (2)

Relative cylinder air charge “rl/rc“ refers to a 100% value defined by the displacement per cylinder and the standard air density. The second influencing variable is the engine speed “n_eng“.

The actual torque value “tqi“ is the result of a multiplication with Lambda- and spark advance efficiencies
eff_lam = fn. (lam) (3)
eff_sa = fn. (d_sa) (4)

(fn. Function of, depending on)

and the reduction factor “eff_red“ caused by a cylinder individual fuel cut-off:
tqi = tqi_opt_l1 * eff_lam * eff_red * eff_sa (5)

(In equations 3 through 5 “lam“ represents Lambda)

For simplification of the basic equation (equation 5), spark advance efficiency is defined depending on the difference between actual spark advance “sa“ and the optimal spark advance:
d_sa = sa_opt – sa

Calculation of the desired values
As previously mentioned, the torque model is not only used to determine the actual value of the internal torque. 
The basic equation (equation 5) can also deliver the desired values of the controller outputs:
tqi_tar = tqi_opt_l1 (rc_tar, n_eng)
* eff_lam_tar
* eff_red_tar

The target torque value “tqi_tar“ is calculated by multiplication of the optimal torque at lamba = 1.0 and optimal spark advance by the efficiencies. Solving equation (6) for “rc_tar“, “eff_lam_tar“, “eff_red_tar“ or “eff_sa_tar“ delivers the target values for the controller outputs which influence torque

d_sa = sa_opt - sa
eff_lam Lambda efficiency
eff_lam_act Actual Lambda efficiency
eff_red Reduction factor
eff_red_act Actual reduction factor
eff_sa Spark advance efficiency
eff_..._tar Target efficiency values
lam Lambda
lam_bas Lambda of basic calibration
n_eng Engine speed
rc Relative cylinder charge
rc_act Actual relative cylinder charge
rc_tar Target value rc
sa Ignition angle reffering to TDC
sa_bas Spark advance of basic calibration
sa_opt Optimal spark advance
sa_opt_l1 Optimal sa at lamda 1.0
tq_i Internal torque, generated by combustion
tqi_bas tqi at sa_bas and lam_bas
tqi_opt, Optimal internal torque
tqi_opt_l1 Optimal tq_i at Lambda 1.0
tqi_tar Target value t_qi


Calculating cylinder charge
The air mass within the cylinder following closure of the intake valve is the air charge. 

There is also a “relative (air) charge” (rl/rc) which is independent of piston displacement. It is defined as the ratio of the current charge to a charge obtained under specified standard conditions: (p0 =1,013 hPa, T0 = 273 K) and used to calculate fuel quantity. 

It is also the primary parameter that influences the engine output, used as a simulation model as there is no way to directly monitor the charge density.

The requirements for the charge model are:
Precise determination of charge density under all operating conditions
Accurate response to exhaust-gas components in systems with variable rate EGR (controlled external or internal EGR),
Calculation of the control command parameter for “throttle-valve aperture” corresponding to any given charge density requirement.

Edited by RBPE
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Inlet manifold simulation model:


The actual mass of the air within the cylinder is relevant for fuel metering and torque calculations and it is calculated using an inlet manifold simulation model due again, to the fact that there is no direct way to monitor charge and therefore requires modelling/simulation.


The inlet mani model can either be monitored directly or simulated depending on MAF/HFM or MAP sensor’s being used by that particular model (HFM/Air mass obviously for the NA VR engines).


The HFM led cars can calculate charge density directly from the induction air mass during static engine operation, but when the throttle is opened there can be a lag due to the manifold plenum having to be filled with air before entering the cylinder. There is a disparity between the air entering the cylinder and what is being measured and it is not until pressure levels rise that the measured air and cylinder air start to be measured more accurately as they equal out.


MAP sensor cars make the manifold pressure a primary factor as the relative charge and manifold pressure can be portrayed using a linear equation.

The linear equation’s offset is defined by the partial pressure emanating from internal residual gases, making it a function of valve overlap, rpm and ambient barometric pressure, while the gradient is determined by engine speed, valve overlap and combustion-chamber temperature.


Other flow into the manifold

Any additional air that isn't entering through the throttle valve (DK), results from activation of such

systems as the evaporative-emissions control. The regeneration flow required by this system can be varied with the aid of a tank vent valve (purge valve). With manifold pressure as a known quantity, it is possible to calculate the regeneration flow for use in the intake-manifold model

simulation process.



Monitoring charge density with the HFM


When the HFM measures the incoming air, it multiplys the mean mass air flow monitored during an intake stroke (segment) by the intake strokes duration for conversion into a relative charge density.

Other aspects of the inlet mani model simulation (such as intake-air temperature) are either monitored directly or calculated in the modelling process (in this case intake-manifold pressure, but also secondary parameters such as combustion- chamber temperature).



Monitoring charge density with a manifold-pressure sensor


Manifold pressure can be monitored directly with MAP systems by calculating the mass of the air entering the inlet manifold based on manifold pressure.


Cylinder charge control


The model for the inlet manifold also controls the density of the charge air entering the cylinder due to the air flow flowing through an orifice/valve (like the throttle plate) , being able to be formulated into an equation.


Main factors calculated within model:

Pressure prior to valve

Pressure drop


Orifice size


Other parameters relevant for specific throttle valves (such as friction losses in the air current) must

be quantified using test-stand measurements.


Once this has been done the manifold model can now be “turned around” to calculate the throttle valve aperture from the desired cylinder charge density (which has been calculated by the torque-led control of the ME system). This aperture is transmitted to the throttle-valve actuator’s position controller as a command value.



Calculating injection timing & Calculating injection duration


The cylinder-charge density can be used as the basis for calculating the fuel mass required to obtain a stoichiometric air/fuel ratio. The injector constant (krkte), which varies according to injector design, can then be incorporated into the calculations to produce the injection duration.


Injection duration is also affected by the differential between the fuel’s supply pressure and injection counter-pressure. The standard fuel supply pressure is generally 300 kPa (3 bar). This pressure can be maintained using any of a variety of reference sources.


Fuel-supply systems with return lines maintain constant supply pressures relative to manifold pressure. This strategy ensures that the pressure differential across the injectors remains constant in the face of changing manifold pressures, so that roughly consistent flow rates result.


Returnless fuel systems rely on a different concept, maintaining their 300 kPa supply pressure relative to ambient pressure. Fluctuations in the pressure within the intake manifold produce variations in the differential between its own pressure and that of the fuel supply. A compensation function corrects this potential error source.

As the injectors open and close they induce pressure waves in the fuel-supply system. This leads to flow-rate inconsistencies when the injector is opened. An adaptation factor correlated with engine speed and injection duration is used to compensate.


The opening duration calculated up to this point will be valid if we assume that the injector has already opened and is discharging fuel at a constant flow rate, but the injector’s opening time must also be considered in real-world operation.

This opening duration displays significant variations depending on the voltage being supplied by the battery. There may be substantial lag before the valve opens completely, especially in the starting phase or when the battery is partially discharged. A supplementary injection duration based on battery voltage is added to the base duration to compensate for this effect.


Excessively short injection durations would lend disproportionate influence to the valve opening and closing times. This is why a minimum injection duration is defined to guarantee precise fuel

metering. This minimal duration is less than the injection period required for minimum potential cylinder charging.




Injection timing

Optimal combustion depends on correct injection timing as well as precise metering. The fuel is usually injected into the intake manifold while the intake valve is still closed. Termination of the injection period is defined by something known as the injection advance, which is indicated in crankshaft degrees, and uses intake valve closure as a reference. The injection duration can then be correlated with engine speed to obtain a point for initiating injection defined as an angle.

Current operating conditions are also reflected in the calculations to define the injection advance angle.


ME-Motronic triggers an individual injector for each cylinder, making it possible to preposition a separate fuel charge for each cylinder (sequential injection). This option is not available with

systems that rely on only one injection valve (single-point injection) or simultaneous activation of several injectors at once (group injection).


Calculating the ignition angle

The “reference ignition angle” is calculated based on the engine’s current steady-state operating status. Its essential determinants are instantaneous cylinder charge, engine speed, and mixture composition (as indicated by the excess-air factor l). The ignition angle is corrected to compensate for the particular operating conditions encountered during starting and in the warm-up phase. A simplified representation of the “reference ignition angle” in ME-Motronic would define it as the earliest potential ignition angle under any given operating conditions. Under standard operating conditions, with the engine warmed to its normal running temperature, this angle is defined by a minimum interval separating it from the knock threshold.


This reference ignition angle can then be further retarded by the knock control (to avoid combustion knock) and the crankshaft- synchronized torque-guidance output (to reduce torque).

The reference ignition angle is combined with the correction factors listed above to produce the so-called “basic ignition angle”.

The actual ignition angle specified by the system reflects the addition of a supplementary correction factor designed to compensate for phase error in the engine-speed sensor.


Calculating the dwell angle

The purpose of the ignition system is to supply enough energy to ensure complete combustion of the air-fuel mixture at precisely the right instant. Energy availability is essentially defined by the dwell period for charging the primary circuit; the end of this period usually coincides with the firing point.

The ECU specifies a dwell angle corresponding to the ignition coil’s charge requirement. It activates the coil’s primary current at the start of the dwell period and then interrupts it to initiate ignition at the firing point. This is how ME-Motronic controls distributorless ignition systems (DLI).

The system refers to a program map to determine the dwell angles for specific engine speeds and battery voltages, while its final output also includes a temperature correction. The start of the dwell period is defined by the difference between the end of dwell and the dwell angle. The dwell angle is calculated from the dwell period using a time/angle conversion equation. The end of the dwell period is defined to coincide with the firing point (ignition timing).

The system basically has two options for defining the start and the end of the dwell period:

As an angle,

As a period of time.

When defined as an angle, the segment time is used to convert the dwell period into an angle. During dynamic variations in engine speed this produces a timing error, as the segment times used for calculating angle position are already outdated. Positive dynamic enginespeed changes (acceleration) lead to attenuated dwell periods, while negative dynamics (deceleration) produce extended dwell angles. Compensation for the dwell period reductions that accompany acceleration is provided by an injection advance, which must always be added to the basic duration. This dynamic injection advance declines as engine speed increases. In contrast, pronounced dynamic changes at low rpm can retard the dwell timing to such an extent that the dwell period becomes too brief for recharging the coil. The response is to transmit the dwell period termination point as a time function at low rpm. This ensures generation of adequate ignition energy regardless of dynamic fluctuations.


Post-start phase

The post-start phase (immediately following termination of the starting phase) is marked by further reductions in the charge densities and injected-fuel quantities employed for starting. System response in this phase is defined by the rise in engine temperature and the period that has elapsed since the starting phase ended.

Ignition angles are also adjusted to correspond to the revised injected-fuel quantities and different operating status. The post-start phase trails off in a smooth transition to the warm-up phase.


Warm-up and catalytic-converter heating

After starting at low engine temperatures, cylinder charge, injection and ignition are all adjusted to compensate for the engine’s greater torque requirements; this process continues up to a suitable temperature threshold.

The prime concern in this phase is rapid warming of the catalytic converter, as quick transition to catalytic-converter operation permits drastic reductions in exhaust emissions. The strategy employs a portion of the exhaust gas for “cat-converter heating” during this phase, while accepting the resulting sacrifices in engine efficiency.

There are basically two concepts:

Secondary air injection into a rich mixture with retarded ignition timing, and

Lean warm-up with extremely retarded (late) ignition timing.

Both concepts entail using retarded ignition timing to operate the engine at a low level of efficiency. The initial results are higher exhaust-gas temperatures and reduced torque generation. The torque-based control automatically compensates for this loss by prescribing higher cylinder-charge densities. This produces a larger quantity of hot exhaust gas for use in heating the catalytic converter with minimal delay. The catalytic converter’s rapid warm-up and the consequent early onset of operation furnish a substantial reduction in exhaust emissions.


Lean warm-up

The combination of lean warm-up with the extremely retarded ignition point leads to the post-oxidization of the unburned hydrocarbons which result from inefficient combustion.

The term “lean warm-up” stems from the use of a slightly lean base mixture to supply the oxygen required to support this oxidation process. Although this concept’s advantage is the freedom to dispense with supplementary components, limits on its potential for heat generation mean that the catalytic converter must be installed close to the engine to minimize thermal losses.


Secondary-air injection

This concept expands on the low efficiency strategy by operating the engine on high levels of excess fuel (l <0.6) to increase the carbon monoxide (CO) and hydrocarbon (HC) content of the exhaust gas. Fresh (“secondary” air which is not involved in the internal combustion process) is then injected directly downstream of the exhaust valves to support oxidation of CO and HC. This produces heat energy, which then flows to the catalytic converter, enabling it to reach operating temperature with minimal delay.

An electric vacuum pump draws the required secondary air from within the air-filter housing or through a special coarse filter. Injection into the exhaust system is then regulated by a deactivation valve and a check valve designed to prevent hot exhaust gases from flowing back into the secondary-air injection system. ME-Motronic triggers the secondary-air pump and air valve at the indicated intervals. A wide-band Lambda oxygen sensor facilitates precise diagnosis of the secondary-air pump. This process produces enough heat for use with catalytic converters situated further away from the engine.



The engine generates no torque at idle; the power generated in the combustion process being needed to sustain engine operation and to drive the ancillary devices. Under these conditions, the torque that the engine needs to remain in operation combines with the idle speed to define fuel consumption.

Because a substantial portion of the fuel consumed by vehicles in heavy stop and-go traffic is actually burned in this kind of use, it pays to hold friction losses during idling at the lowest possible level. This translates into specifying low idle speeds.

ME-Motronic’s closed-loop idle control reliably maintains a stable idle at the defined level regardless of variations in operating conditions. These variations can stem from from factors such as fluctuating current draw in the electrical system, air-conditioner compressors, gear engagement on automatic-transmission vehicles, active power steering etc.


WOT (full load)

At Wide-Open Throttle (WOT) there are no throttling losses, and the engine produces the maximum potential power available at any given rpm.


Transition response Acceleration/deceleration

A portion of the fuel discharged into the inlet manifold does not reach the cylinder in time for the subsequent combustion process. Instead, it forms a condensation layer along the walls of the

inlet manifold. The actual quantity of fuel stored in this film rises radically in response to higher load factors and extended injection durations.

A portion of the fuel injected when the throttle valve opens is absorbed for this film. As a result, a corresponding quantity of supplementary fuel must be injected to compensate and prevent the mixture from going lean under acceleration.

Because the additional fuel retained in the wall film is released again once the load factor drops, injection durations must also be reduced by a corresponding increment during deceleration.


Overrun fuel cutoff/renewed fuel flow

Overrun, or trailing throttle, indicates a condition in which the power being provided by the engine at the flywheel is negative. Under these conditions the engine’s friction and gas-flow losses can be exploited to slow the vehicle. The engine can continue to run with or without active fuel injection.

For passive, injectionless trailing-throttle operation the injection is deactivated to reduce fuel consumption and exhaust emissions. ME-Motronic’s torque-based control can regulate suppression of the fuel-injection pulses to prevent radical torque jumps during the transition to trailing throttle by relying on gradual instead of abrupt reductions in specified output.

Injection resumes once rpm falls to a specified reactivation speed located at a point above idle. Actually, the ECU is programmed with a range of reactivation speeds. These vary to reflect changes in parameters such as engine temperature and dynamic variations in engine speed, and are calculated to prevent the rpm from falling below the defined minimum threshold.

Once injection resumes, the system starts by using the initial injection pulses to discharge supplementary fuel and rebuild the wall fuel layer. When fuel injection is resumed, the slow, controlled increase of engine torque by the torque based control ensures that torque build up is smooth (gentle transition).


Closed-loop idle-speed control


The engine does not furnish torque at the flywheel during idling. To ensure consistent idling at the lowest possible level, the closed-loop idle-speed control system must maintain a balance between torque generation and the engine’s “power consumption.”

Power generation is needed at idle in order to satisfy load requirements from a number of quarters. These include internal friction at the engine’s crankshaft and valve-train assemblies, as well as such ancillary equipment as the water pump. The engine’s internal friction losses are subject to substantial variation in response to temperature fluctuations, while friction also changes, albeit at a much slower rate, over the course of the engine’s service life.

The load imposed by external factors (such as the a/c compressor) also fluctuates through a wide range as ancillaries are switched on and off. Modern engines are especially sensitive to these variations, owing to their lower reciprocating and flywheel masses as well as higher inlet manifold

(storage) volumes.


Operating concept

ME-Motronic’s torque-based concept relies on closed-loop idle-speed control to quantify the output needed to maintain the desired idle speed under any operating conditions. This output rises as engine speed decreases, and drops as it increases.

The system responds to recognition of new “interference factors” such as activation of the a/c compressor or engagement of a drive range in an automatic transmission by requesting more torque.

Torque demand must also be increased at low engine temperatures to compensate for higher internal friction losses and/or maintain a higher idle speed. The sum of all these output demands is relayed to the torque coordinator, which then proceeds to calculate the corresponding charge density, mixture composition and ignition timing.


Lambda - closed-loop control

Post-treatment of exhaust gases in a 3-way catalytic converter represents an effective means of reducing concentrations of harmful exhaust pollutants.

The converter can reduce hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOX) by 98% and more, converting them to water (H2O), carbon dioxide (CO2) and nitrogen (N2). This level of efficiency is contingent on engine operation within a very narrow scatter range surrounding the range surrounding the stoichiometric air-fuel ratio of l = 1.


Two-state lambda closedloop control


Control range

The “lambda window,” corresponding to the range available for effective simultaneous processing of all three “classical” exhaust-gas components, is extremely restricted. Closed-loop lambda control is needed to maintain operation within this window (l = 0.99...1).

The two-state oxygen sensor monitors the exhaust stream’s oxygen content from a position on the engine side of the catalytic converter. Lean mixtures (l > 1) induce sensor voltages of approx. 100mV, while rich mixtures (l < 1) generate roughly 800 mV. At l = 1 the sensor voltage suddenly jumps from one level to the other.

ME-Motronic includes this signal from the oxygen sensor in its calculations of injection duration.



A closed-loop lambda control system can only function in tandem with a fully operational oxygen sensor. An auxiliary processing circuit monitors the sensor on a continuing basis.

A cold oxygen sensor or damaged circuitry (short or open circuits) will lead to implausible voltage signals, which the ECU will reject. Depending upon individual configuration and installation position, the heated oxygen sensors found today in most systems can assume operation after only 15 to 30 seconds.

Cold engines require a richer mixture (l < 1) to run smoothly. This is why the closed-loop lambda control circuit is only released for active intervention once a defined temperature threshold has been reached.

Once the lambda control assumes operation, the ECU uses a comparator to convert the sensor signal into binary form.

The lambda closed-loop control reacts to incoming signals (l > 1 = mixture too lean, or l < 1 = mixture too rich) by modifying the control variables, generating a control factor for use as a multiplication factor when modifying the injection duration.

Injection duration is adjusted (lengthened or reduced) and the control factor reacts by settling into a state of constant oscillation.

Continuing oscillation in a range with l = 1 as its focal point is the only way to achieve optimal lambda control with a dual-state system. The precision of the closed-loop control process depends upon the speed with which the control system can adjust the control factor to counteract shifts in the excess-air factor. While waiting fuel is constantly being discharged into the combustion chamber, the O2 sensor is located elsewhere, further back in the exhaust system. The resulting gas-transit times translate into response lag within the control circuit, with the actual delay depending on the engine’s load factor and speed. The ultimate reaction to mixture adjustments can only be measured once the lag period has elapsed. This leads to a minimum phase duration (periodicity) for the cyclical revisions in the control factor.

Processing times and the sensor’s response delay increase lag even further.

The duration of the oscillation periods is determined by the transit times of the gas, while the ramp climb maintains largely constant amplitudes throughout the engine’s load and speed range, despite variations in gas-transit times. Radical steps in control factor during mixture adjustments (sensor jump) accelerate the reaction process, making it possible to shorten the oscillation period.


Lambda shift

Because the sensor’s response pattern varies depending upon the direction of the monitored mixture transition (viz., rich to lean, or lean to rich), a symmetrical control arrangement would produce a slightly lean exhaust mixture. Because catalytic converter efficiency is optimal in the l = 0.99...1.0 range, the control system must be able to counteract this tendency. An asymmetrical controller oscillation pattern can shift the mixture into the optimal conversion range.

The required asymmetry is obtained either by delaying the switch-over of the control factor after the voltage jump (from lean to rich) at the oxygen sensor, or with an asymmetrical step function. Maximum are limited to maintain the controller’s dynamic response.


Adapting the Lambda pilot control to the Lambda closed-loop control

The lambda closed-loop control system corrects each consecutive injection event in the sequence based on previous monitoring data from the O2 sensor. As a result, a certain time shift arising from gas-transit times is unavoidable, and the approach to new operating points defined with maladjusted pilot control is characterized by deviations from l = 1. This condition continues until the system’s cyclical control can reestablish equilibrium.

Thus a special default (or reference) control mechanism is needed to maintain compliance with emissions limits. The pilot control is programmed when the system is adapted to the engine, and a corresponding lambda control map is stored in a ROM (program memory).

However, subsequent revisions in the default control may be needed to compensate for the effects of drift factors during the vehicle’s service life, including variations in the density and quality of the


If the lambda controller starts to consistently implement a single set of corrections during operation in a particular engine speed and load range, the pilot control’s adaptation function will register this fact and respond by programming corresponding corrections into the system’s non-volatile memory (RAM or EEPROM with constant current supply). The corrected pilot control is then ready for immediate implementation at the next start, assuming duty until the lambda closed-loop control becomes active.

Interruptions in the power supply to the non-volatile memory are also registered; adaptation then recommences using neutral pilot-control values as a starting point.


Dual-sensor lambda closed-loop control

Installing the oxygen sensor at the back end of the catalytic converter (“cat-back” position) helps guard it against contaminants in the exhaust gas while also reducing the thermal stresses imposed on it. This type of auxiliary sensor can generate a second, overlapping control signal to augment the one from the main, (“cat-forward”) sensor on the engine side and ensure stable airfuel mixture composition over an extended period.

The superimposed control system modifies the asymmetry of the constant oscillation pattern that characterizes control mechanisms based solely on a cat-forward oxygen sensor; thus compensating for the lambda shift.

A lambda control strategy based exclusively on a sensor mounted behind the converter (“cat-back”) would be handicapped by excessive control lag produced by extended gas-transit times.

While helping maintain the lambda control system’s long-term operational stability, the second, “cat-back” sensor also can be employed as a tool for assessing the catalytic converter’s effectiveness.


Continuous lambda closedloop control

While the two-state sensor can only indicate two states – rich and lean – with a corresponding voltage jump, the wideband sensor monitors deviations from l = 1 by transmitting a continuous signal. In other words, this wide-band sensor makes it possible to implement lambda control strategies based on continuous instead of dual-state information.

The advantages are:

A substantial improvement in dynamic response, with quantified data on deviations from the specified gas composition, and

The option of adjusting to any values, i.e., also air factors other than l = 1.

The second option is especially significant for strategies seeking to exploit the fuel-savings potential *** Also - hence the “get a WB 02 monitor!” ***


Evaporativeemissions control system

Source of fuel vapors

The fuel in the tank is warmed by:

Heat radiated from external sources, and

Excess fuel from the system return line, which is heated during its passage through the engine

compartment. This results in HC emissions which primarily emerge from the fuel tank in the form of vapor.


Limiting HC emissions

Evaporative emissions are limited by legal mandate. Limitation is by means of evaporative-emissions control systems equipped with an activated-charcoal filter (carbon canister) installed at the end of the tank’s vent line. The activated charcoal in the canister binds the fuel vapors, allowing

only air to escape into the atmosphere, while simultaneously providing the pressure- relief function. To support ongoing regeneration in the charcoal filter, an additional line leads from the canister to the intake manifold.


Knock control

Electronic control of ignition timing allows extremely precise adjustment of advance angles based on engine rpm, temperature and load factor.

Despite this precision, conventional systems must still operate with a substantial safety margin to avoid approaching the knock threshold. This margin is necessary to ensure that no cylinder will reach or go beyond the pre-ignition limit, even when susceptibility is increased by risk factors such as engine tolerances, ageing, environmental conditions and fuel quality. The engine design which results when these factors are taken into consideration features a lower compression ratio with retarded ignition which lead to sacrifices in fuel consumption and torque.

These disadvantages can be avoided by using a knock-control system.

Experience confirms that such a system allows higher compression ratios, with considerable improvements in both fuel economy and torque. With this system, it is no longer necessary to specify pilot ignition-timing angles defined to reflect worst-case scenarios. Instead, ideal conditions (engine compression at tolerance threshold, maximum fuel quality, cylinder least prone to preignition) can serve as the basis for specifying ignition timing. This makes it possible for each cylinder to be operated at the pre-ignition limit, which coincides with optimal efficiency, in virtually all ranges, and throughout the life of the engine.

The essential prerequisite for this kind of knock-control system is reliable detection of any and all pre-ignition exceeding a specified intensity. This must embrace every cylinder and extend throughout the engine’s entire operating range.

Pre-ignition is detected by sensors designed to register solid-borne sonic waves. Installed at one or several suitable points on the engine, these knock sensors detect the characteristic oscillation patterns produced by knock and transform them into electrical signals suitable for transmission to the Motronic ECU for subsequent processing (refer to the section on ignition for additional information). The ECU employs a special processing algorithm to detect incipient pre-ignition in every combustion cycle and in every cylinder. Detection of knock triggers a specified, programmed reduction in ignition advance. When the knock danger subsides, the ignition for the affected cylinder is then gradually advanced back toward the pilot ignition timing angle.

The knock-recognition and knock-control algorithms are designed to prevent the kind of pre-ignition that results in audible knock and engine damage.



Real-world engine operation is characterized by different knock limits in different cylinders, and ignition timing must be adjusted accordingly. In order to adapt the pilot-ignition timing to reflect the individual knock limits under varying operating conditions, individual ignition retard increments are stored for each cylinder.

These data for specific engine speeds and load factors are stored in non-volatile program maps in permanently-powered RAMs. This strategy permits the engine to be operated at maximum efficiency under all conditions without any danger of audible combustion knock, even during

abrupt changes in load and rpm. The engine can even be approved to run on low-octane fuels. Standard practice is to adapt the engine to run on premium fuel. Operation with regular-grade petrol can also be approved.



Boost-pressure control

Boost-pressure control mechanisms that rely on pneumatically-triggered mechanical layouts use actuators (wastegates) that are directly exposed to the pressure in the impeller outlet. This

concept allows only very limited definition of torque response as a function of engine speed. Load control is limited to the full load bypass. There is no provision for compensation of the full-load boost tolerances, and at part load, the closed wastegate impairs operating efficiency.

Acceleration from low rpm can be marked by a delay in turbocharger response (a very pronounced “turbo lag”). These problems can be avoided with electronic boost-pressure control. This system can provide reductions in specific fuel consumption under some part throttle operating conditions, controlling the wastegate’s opening pattern to obtain the following results:

The engine’s back-pressure losses and the impeller’s output both drop,

Pressure and temperature at the impeller’s discharge orifice fall, and

The pressure gradient at the throttle valve is reduced.

The exhaust-gas turbocharger and its boost-control device must be precisely matched to the engine as the primary requirements for achieving these improvements.

The affected components in the boost control device are:

The electro-pneumatic cycle valve,

The effective diaphragm surface, stroke and spring in the aneroid capsule, and

The cross section of the valve head or valve flap in the wastegate.


ME-Motronic employs electronic boost control to regulate induction pressure to the specified value. This specified boost pressure is converted into a specification for the desired maximum cylinder charge. The torque-based control function converts this specification into a setpoint for throttle-valve aperture and a pulse duty factor for the wastegate. The signal modifies the wastegate’s control pressure and stroke to regulate the bypass opening.

Control-circuit elements compensate for the difference between the setpoint defined by current operating conditions (program map) and the actual, monitored boost pressure. The calculated value at the controller output is then included in the process used to define the maximum cylinder charge.

On turbocharged engines, the temperature of the exhaust gas between engine and turbine should not exceed certain limits. This is why Motronic’s boost control operates exclusively in conjunction with knock control, as the latter represents the only means for operating the engine with maximum ignition advance throughout its service life. A result of using optimal ignition timing at all operating coordinates is extremely low exhaust-gas temperatures. Further reductions in exhaust temperature are available through intervention in cylinder charge, meaning boost pressure in this case, and/or air-fuel mixture.


Protective functions - Limiting vehicle and engine speed

Extremely high engine speeds can lead to power plant demolition (valve train, pistons). The rpm limiting function prevents the maximum approved engine speed (redline) from being exceeded. Incorporation of a vehicle-speed limiter may be necessary in response to specific equipment specifications as defined for vehicles in certain markets (i.e., tires, suspension). In addition, several German manufacturers have made a voluntary commitment to limit the maximum speeds of their vehicles to 250 km/h. The functions for restricting vehicle and engine speeds operate according to the same principles. A control agorithm reduces the permitted engine output once a specified threshold is crossed. This output limit is included in ME-Motronic’s torque-based control function.


Torque and power limits

It is sometimes necessary to restrict torque generation in order to reduce the loading on certain drivetrain components (such as the transmission). ME-Motronic’s torque based control function provides for the definition of such a limit. It is also possible to restrict ultimate output by governing engine speed and torque.


Limiting exhaust-gas temperatures

High exhaust-gas temperatures can damage exhaust-system components. Therefore, a model incorporated within the ECU is employed to simulate these temperatures. Extreme requirements for monitoring precision can be satisfied by installing a temperature sensor. Temperatures beyond a defined threshold trigger mixture enrichment, which cools the exhaust by extracting heat energy to vaporize the fuel. Limiting charge density and torque are additional options.


Vehicle immobilizer

To prevent unauthorized vehicle use, the Motronic ECU incorporates a feature that prevents the engine from being started until the ECU itself has been released via a special control line. The actual release mechanism is an encoded signalm prepared by an external control unit. This second control unit verifies user authorization by analyzing the signal from a transmitter in the ignition key or a keypad entry code, etc.


Improved drivability/Transition surge-impact suppression

Positive and negative load shiftsinitiated by abruptly depressing or releasing the accelerator pedal can produce jolts in the driveline. This effect is especially pronounced when the torque reversal transfers forces to mounting bushings or the transmission.

An example is the engine, which shifts from one engine mount to the other during transitions from power-on to power-off.

This force transfer can be prevented, or at least reduced in intensity, by controlling the rates of torque rise and reduction in order to achieve gentler transitions. In order to adjust flywheel torque this strategy relies on manipulation of ignition timing and cylinder charge.


Surge-damping function

The fact that the engine and drivetrain represent a spring-mass system means that during operation this system can start to oscillate. The surge-damping function detects these oscillations and suppresses them by intervening in engine output torque in the respective phase.


So, we have a great overview on how the ME7.1.1. and other ME7 systems work, a good basic knowledge on theolder Motronic 2/3/5 systems for your 12V, it's now about building the VR/R32 specific ecu's up for definition!

Edited by RBPE
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On 4/30/2016 at 8:37 PM, VR6Pete said:

Top work! Really good read!

More to come  - it is how the ME7 ecu's work, correct caliibration procedures. Bit of change with the earlier mk3's but you only need to look for the main maps and have made English def files like the one you've seen. Look at the Z's for Zundung - ignition and ZW adds winkel for angle, K for knock/ klopfen , E for injection/ Einspritzung etc

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  • 4 weeks later...

If you're following this then here's a nice easy way to start learning what's on your ecu - this is a demo for mk4 owners but similar principles for any car, just what files you can get.


So, if you want to learn what's on the mk4 ecu's (or some of it anyhow), here's what you can do;


First, get the demo version of winols here;



I did this very quick def file for a guy on Nefmoto with a BDF car (same as our BDE twin VVT V6's) so we'll use that - some of it is English and some in German as I used various files to define it so any German you'll have to translate. There's some nifty programs that can do it that some tuners have posted up but I would just get used to changing German in Google translate. To do that in the demo you click open the map/function, right click - properties - change the text and okay it.


Once you've done that, click here and put this into the winols demo;




You'll get checksum requests just press cancel for both files as it's the demo version anyway and not needed for this, plus it's already checksummed.


I chose the mk4 R32 CP stock file for this example, I suppose you can use any 022906 mk4/5 V6/R32 file from the page or even your own though;

So, now you've got a bit of a definition file, let's compare to it to a stock read. I chose the 032CP mk4 R32 file from here for this example;



Again, drag and drop that into winols, cancel the checksum requests and then connect the two files (view - connect windows). Should look a bit like this (this is the 12v one from above though);



So, you should have two files lined up, one partially defined and one a blank stock read. As you can see now, it is green and lined up at the beginning (if you're using the same two as I am at least) - but as you scroll down it'll change colour where the maps are, this is due to offset differences or ecu differences where their are either extra bytes or simply the math is different.


If you are using the same two, the KLAF map in BGRLP amongst other areas should line up. However, there are a few little tricks to line the mk4/5 ecu's up.


Firstly, the dwell angle map in ZUESZ (8x8 map) is usually identical between variants so that should line up in many to start defining;



and the other area that you can line a lot of the different model/ecu's up on the V6/R32's is in GGHFM.


These vehicles use the 5 series HFM (MAF to most) and have a 512x1 map for linearization of the meter (in GGHFM on the def file it is called "Linearisierung der Heißfilmspannung"). If you go to this map (right click, view in hexdump) you will see it doesn't show up as being in the R32 CP stock file (will show up the same in other V6's though). There are numerous ID's used for the MAF's between variants and obviously the 62mm ID will not be the same as the 71, the low flow ranges are slightly lower or higher etc as you can see - this equals some obvious different figures.



Anyway, here's the trick in this area then when defining between models. These maf's have a reverse flow offset of 200kg "Kennlinienoffset HFM 5" in the def file. Right click that and view in hexdump. It will say there is one in the other file (red arrow showing up) but there are many areas with the same value and it probably won't line them up correctly. So, with the mk4 V6 and R32's there is also a 4kg/hr minimum air mass level too - it shows up as below right next to the 200kg offset values.


The values you are looking for are; 28 00 D0 07


If you highlight them together (you do this by clicking on one number and holding down the left mouse button as you go across the four values shown - i.e. left click the 28 and highlight it to the 07) then you should now see two red arrows pop up. The bottom one is a single area location - too many of the same number to use that, the arrow in the middle though is area's line up the same (i.e. from 28 through to 07). That's the one you click and it should come up with only one area the same as that.


Once you do that it should line up perfectly so you go to the bit at the bottom that says "transfer map structure" (the middle window under copy in between the two ecu files). What you are doing is simply copying the structure of the maps from one side (usually the blue def file will be on the left) to the other. So if your def file is on the left you're clicking the right arrow and if your def file is on the right, click the left arrow. *** "Don't transfer values, just the structure!" *****


Because these are always after the main HFM linearization map on these ecu's, you can then press delete once you've transferred the structure (this stops highlighting those values) and then left click on the 512x1 big blue defined map of the HFM and again transfer the structure of the map. This 512x1 map should be linear and usually starts at 155.1 or so with the V6's and 148 point something with the R32's. The battery voltage should go from 0 to 5 (or 4.99 something) volts. If so, then you've done it right and I know people who have practiced with winols for months who still struggle defining the maps correctly and I have seen very expensive pro tunes with such maps all over the show (mappers tend to use DAMOS files, easier but not really right, this is a form of manual reverse engineering a bit and should help you to pick out patterns of hex code int he future!).


What to look for;







Any probs let me know - this should cut your defining time somewhat!



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Guest G60Dub

So reading the above would it be considered foolhardy to code out the rear O2 sensors on a BFH given they are also used to trim out the long term sensor drift of the pre CAT sensors?

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On 5/30/2016 at 11:05 AM, Guest G60Dub said:

So reading the above would it be considered foolhardy to code out the rear O2 sensors on a BFH given they are also used to trim out the long term sensor drift of the pre CAT sensors?


Not necessarily, you strip the functional logic to it's bare bones you can essentially make it do what you want in that respect, switching off the codewords in the map areas that use the rear 02 for example to "off" 00, from "on" 01, or;


Take, for example, placing the two probes into one downpipe - this caused LTFT problems as the ecu expects to see two different readings but when placed together like that they are generally identical. It then confuses the ecu and so it adapts to make it logical again which eventually causes it to go out of sync as it keeps adapting further and further over time. 

However, if you know how the system works and can manipulate the ecu then you can change it's functional logic so that you can place one probe into a downpipe and then have the ecu think it is reading from both banks instead of what it is actually doing and happily accepting that. Plenty of these have been done that way without any problems.


The main problem with this is the time it takes to properly reverse engineer and you need proper full reads of ram addresses etc that most flash tools don't provide, plus the disassembly and patching involved, hence why it's usually easier to use pre-turbo 02 placements, fuel tweaking is preferred over laborious reverse engineering.


To get you started;


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  • 1 month later...

p.s. Ultimately too, these ecu's will read directly from the 02's in an emergency with the primary 02's being paramount, you can manipulate everything else to varying degree's after that.

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  • 2 months later...

There's a partial definition file for the US BDF here I did quickly, should help you do some mk4 stuff at least if you want to define your own sticking it into winols demo and making a Tunerpro file. Various bit's and bobs, probably best links on the net for making your own files for mk4 though at the moment;




Some English def's ect, ran the files through disassemblers and such programs if you need asm code let us know. Should help if you've been hunting down DAMOS packs and data isn't lining up right! 


Beware - a lot of the DAMOS files for these have been heavily modified, almost like turbo one's but with questionable changes, I've also noticed there are some that seem to be 2.8's dressed up as R32's, you have to go into the litres/volumes maps you've likely not heard of on the net which show they're 2.8's not 3.2's as they are hard to find.



CAN CC Hybrid R32 mk4 v BDE


Start with your stock ecu and build it on that imho!

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  • 6 months later...

I know his is an old thread and this is a lot of information that I need to read a lot more detailed however I have been informed that the AUE engine is not as easy to mod and it is non VVT. Is this correct?

If so what route is best to take with this engine. I am only asking here as you have stated all 24v variants are the same. 


Thank you 

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All ME7 is fundamentally the same to a large degree, just various evolutions and parts differences of course, this in turn adds maps/data and changes a few things.


AUE/Early 2.8 24v models have Inlet cam timing but no exhaust, Nokenwellen Einlass maps are there (NW-E abbrv. you should get used to), Auslass (NW-A) are not, generally everything else pretty much the same. Values will change due to a lack of input data when there are maps missing - if trying to define you need to look at axis data rather than cell data if using, for example, a dual VVT def file or R32.


BDE/BDF - late 24v's had both inlet and exhaust cam timing, I think the differences between these are number of 02's due to exhaust differences because ours (UK/EU) were  V6 4 motions whereas US were VR6 24V and fwd so different exhaust routings due to propshaft etc but never really done anything with BDF apart from some quick def's.


BFH R32 MK4 - Pretty much the same as BDE only obviously the displacement changes make differences, max torque across CAN etc are upped so some values different like that. They used larger parts like MAF (HFM actually now) so HFM map values/limit's different, low flow rates etc - flow across throttle body and general flow/tb/maf related values are changed due to this. This in turn leads to different maths/logic so many figures different over the 2.8's.


MK5 R32 - Part changes and increased limit's as above really, slight variances again in torque limit values across can and things like that, cam maps, homo/stratified injection, HFM 6 series etc - general evolution of maps there, some other things I can't think of the moment.


AUDI TT - Both mk1 and mk2 TT's use different HFM main maps like Porsche use on the ME7.8 and later ME9 stuff which in turn changes the structure of some maps, A3 ecu's I have done matched the mk5 one's though - everything else I think was pretty much the same as mk5 with only a few minor differences you should be able to see with a good def file.


DSG/Auto v Manual - if doing an engine swap with gearbox change you should use an ecu with that gearbox as you can get all sorts of pedal/flow/rpm play ups, use the ecu for the gearbox is the easiest way really. Same for hybrid conversions, easier to code out than add custom code to it in redundant areas.


That's just some off the top of my head, but even with these kind's of evolutions, the vast majority of data is fundamentally the same or similar, not sure where I "stated they are all the same" as I have always said AUE are inlet vvt, but it's what you can see on the screenshots in the backgrounds or map data shown; very similar in terms of functions overall being ME7.1.1. but different figures due to above and the maths/logic the ecu needs basically.


Example - HFM (maf) variances as stock (HFM 5 but diff sizes mk4 V6 4mo v mk4 R32 here, then v's mk5 HFM 6 series) - MLHFM main map flow kg/hr and min flow; BDE v BFH v BUB

MLHFM & Min mass V6 R32 mk4 mk5


In terms of data stacking/location, as they are all C166 evolutions they are very similar, like the background's in the screenshots as opposed to, in this case, individual data in a cell;

KUMSRL Conversion mass flow


So they are very similar and yet can be different, but no, no special differences between any 2.8's, just some market variances, part/ecu evolutions and more or less data to play with ultimately!


**Also note that mk4 C167 (C166 evolutions) are stacked one way and C167 ST10 (mk5) are flipped, same in DSG reads;


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30 minutes ago, RBPE said:

All ME7 is fundamentally the same to a large degree, just various evolutions and parts differences of course, this in turn adds maps/data and changes a few things.


AUE/Early 2.8 24v models have Inlet cam timing but no exhaust, Nokenwellen Einlass maps are there (NW-E abbrv. you should get used to), Auslass (NW-A) are not, generally everything else pretty much the same. Values will change due to a lack of input data when there are maps missing - if trying to define you need to look at axis data rather than cell data if using, for example, a dual VVT def file or R32.


BDE/BDF - late 24v's had both inlet and exhaust cam timing, I think the differences between these are number of 02's due to exhaust differences, but never really done anything with BDF apart from some quick def's.


BFH R32 MK4 - Pretty much the same as BDE only obviously the displacement changes make differences, max torque across CAN etc are upped so some values different like that. They used larger parts like MAF so HFM map values/limit's different, low flow rates etc - flow across throttle body and general flow/tb/maf related values are changed due to this.


MK5 R32 - Part changes and increased limit's as above really, slight variances again in torque limit values across can and things like that, cam maps, homo/stratified injection - general evolution of maps there, some other things I can't think of the moment.


AUDI TT - Both mk1 and mk2 TT's use different HFM main maps like Porsche use on the ME7.8 and later ME9 stuff which in turn changes the structure of some maps, A3 ecu's I have done matched the mk5 one's though - everything else I think was pretty much the same as mk5.


DSG/Auto v Manual - if doing an engine swap with gearbox change you should use an ecu with that gearbox as you can get all sorts of pedal/flow/rpm play ups, use the ecu for the gearbox is the easiest way really.


That's just some off the top of my head, but even with these kind's of evolutions, the vast majority of data is fundamentally the same or similar, not sure where I "stated they are all the same" as I have always said AUE are inlet vvt but it's what you can see on the screenshots in the backgrounds or map data shown;

Example - HFM (maf) variances as stock - MLHFM main map flow kg/hr and min flow; BDE v BFH v BUB

MLHFM & Min mass V6 R32 mk4 mk5


In terms of data stacking/location, as they are all C166 evolutions they are very similar, like the background's in the screenshots as opposed to, in this case, individual data in a cell;

KUMSRL Conversion mass flow


So they are very similar and yet can be different, but no, no special differences between any 2.8's, just some market variances, part/ecu evolutions and more or less data to play with ultimately!

OK so in this case, I can get a tuner to flash my ECU for my engine much the same as the BDE? 

Take UnitedMotorsports for example, I can I a UM flash for my car and build the car to the supporting mods? Is this availabile? 



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  • 1 year later...

All ME7.1.1. are 022906032 - the variances between them are; inlet only vvt, full inlet, 2 point exhaust vvt, 02 number variances and limiters and removals market depending,  engine and cyl volume variances in the ecu, dsg v manual, hfm maps and the evolution of the c166 which I think has at least 3 variances (early c167, c167 evolution/hybrid and st10) and differences in protocols/immo aspects between c167's and st10's, so certain tools can work on early but not the later st10........ these are just some of the differences off the top of my head between the 022 906 032 only on VW/Audi 2.8's and 3.2's, let alone anything else that may use 022 906 032! 


You can have 2 identical letters like the mk5 CD here but they can have differences in them, this is usually market led and some tweaks to maps to suit if I remember right -


ECU Codes 022906032


Otherwise variances like CD v CE can be the same ecu's for the market but one is auto/dsg and one is manual. 


You can modify the data to suit if you know what you are doing like dsg/manual swaps like I showed Hummel below how to start doing it, but if not, I would try and get the exact same one or as close as possible in your market




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Thanks for the info.

I understand that reading flash/eeprom from my 022 906 032 BE and writing it 022 906 032 BT will be hit and miss?

I don't plan to do a plug and play swap. I want to create a clone spare ecu based on the content of my ecu, no tuning.

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1 hour ago, VR6Treg said:

Thanks for the info.

I understand that reading flash/eeprom from my 022 906 032 BE and writing it 022 906 032 BT will be hit and miss?

I don't plan to do a plug and play swap. I want to create a clone spare ecu based on the content of my ecu, no tuning.


I know what you are saying but even with the same letters there can be differences, not that they wouldn't cross flash although there can be problems there as mentioned, just that maps alone have differences.

BT is coming up as a Porsche Cayenne ecu with some people touting it as Porsche and Toureg. As an example this is a Cayenne one against and VR6 24V one (032T v's 032BM) - you can see a very similar structure (green) but you can also see differences between maps due to all the reasons mentioned. Like I say, if you don't know how to modify this data it could have problems, best bet is to get as close to your model as possible if not the same one and take it from there! 


032T v 032BM Structure


Best answer I can give you without looking at the ori reads directly and reversing them a bit.

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I get it but not there yet :-)

I was thinking of it like this: ecu is a computer which runs an operating system. When you flash it you're installing the operating system of your choice. I thought the flash/eeprom programming will make the ecu a full clone of the original if the hardware is the same. 

The closest I can get is an ecu with the same letters for a 3.2 VR6 Touareg but not the same engine.

I'll start with this one and see how it goes.

This is my first attempt at ecu cloning and this is only a personal project to have a spare ecu so sorry to bother you with basic stuff: What kind of data is there in the comparison pics? I mean is it flash or eeprom or something else? 

I can upload an eeprom dump of my ecu if that helps. 


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On 17/03/2019 at 4:22 PM, VR6Treg said:

I get it but not there yet :-)

I was thinking of it like this: ecu is a computer which runs an operating system. When you flash it you're installing the operating system of your choice. I thought the flash/eeprom programming will make the ecu a full clone of the original if the hardware is the same. 

The closest I can get is an ecu with the same letters for a 3.2 VR6 Touareg but not the same engine.

I'll start with this one and see how it goes.

This is my first attempt at ecu cloning and this is only a personal project to have a spare ecu so sorry to bother you with basic stuff: What kind of data is there in the comparison pics? I mean is it flash or eeprom or something else? 

I can upload an eeprom dump of my ecu if that helps. 



What you can do on these or any ecu really, depends on how well, or not, your flashing tool interacts with the ecu plus what you use to read the data with. You can get tools that will not only give you the flash but also the mcu etc as well, even then the data within it could be off depending on what tools you are using to read/reverse it.

Even if you use a normal tool and just get the usual data/eeprom for flashing like on most tools, then even then tools can vary on the data given, a point I was trying to get at in the BDE tuning thread - some tools you'll have rpm data there to change as you wish, some will cover it up so you don't change the rpm's accidentally or they'll shift things around for safety reasons.


So it simply comes down to the tools you're using, their protocols/how they interact with the ecu, not all will just cross over all the data. Not only that but on later ones like ST10 you have immo in the mcu aspects and so on to think about when you flash, THEN it depends on how well your reversing/reading tools are too it seems!

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