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tkoral

VR6 dizzy no spark but fuel after rebuild

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I finished up a full rebuild to my 2.9 VR6 and now it will not get spark to the plugs.

Coil wire has 11.8v to distributor.

Crank sensor shows 900 ohms

Female plug that connects to the distributor shows 12v on one pin and 5v on the other.

Unable to get any ohms reading across the hall sensor male connector pins.

Did my hall sensor go out or could it be a fried ecu?

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Can you confirm you cranked the engine (on the key) with the spark plug base against the engine - and no spark was observed.

 

The distributor has a 3-pin connector:

pin 1 - 0v

pin 2 - timing signal from the ECU

pin 3 - 12v

 

The hall sender is also a 3-pin connector:

pin 1 - 0v

pin 2 - signal to ECU

pin 3 - 12v

 

Check the power is present across pins 1 and 3.

The distributor is powered by the ignition (terminal 15) and the hall sender is powered through Relay 3 - the ECU power supply relay - sharing power with the injectors.

You will need an oscilloscope to see the output of the hall sender.

I suppose you could remove the sensor from the engine, put 12v across pins 1 and 3 and measure the output across pins 1 and 2 as you waft a screwdriver across the end of the sensor. It will probably be a small voltage, but may be detectable?

 

Are there any clues/faults in the ECU which could guide you?

 

 

When I rebuilt my engine, I had fuel and a spark - just not at the same time (the bottom end was 180 degrees out).

So, check everything as you go along. And if there is still doubt, prove your assumptions are still correct!!

 

Report back with how you get on.

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I connected my multimeter to the ignition coil lead wire to the dizzy.

I get 12v when the key is in the on position. When I cycle the key for a engine start the voltage with that lead drops to around 7v.

I am unable to gather any faults. I do not have vag com unfortunately.

I will try to see if I'm getting a signal from the hall sensor tonight. I know I am getting 12v power and 5v signal from the plug that attaches to the hall sensor.

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Did you confirm if the spark plugs were sparking, when cranked on the key?

 

I cannot see the ECU blowing, unless something extreme happened to it. Engine sensors are pretty robust, too.

 

So you have power on the engine sensors.
Is the engine and distributer timing definitely correct?
Are the HT leads correctly installed?
Can you smell fuel on the plugs?

 

Does this thread help you any??

http://the-corrado.net/showthread.php?39951-VR6-Distributor-timing-rotor-alignment

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I apologize for not keeping you updated Philly-R6. I've been tremendously busy with non VR6 things. I am at a stand still till the postal service drops off my new ignition coil tomorrow.

I was not getting an actual spark from any plug. The ignition coil was only giving the plugs around 7v to produce spark with. I've been told that the voltage coming from the ignition coil should be in thousands.

I tested the resistance of my ignition coil and the primary resistance checked out good. The secondary resistance tested at 7.75 ohms in the 20k ohm range. The Bentley calls for the secondary resistance range to be between 3,000- 4,000 ohms.

The distributor timing is correct. I tried to flip it 180 on the cam gear and found out it's impossible with the way it's keyed. I had everything timed correctly after installing the chains.

I'm thinking and hoping it's just the ignition coil that has gone bad. All of my sensors are plugged in correctly and are showing 12v at power pins at all plugs with at least 2v for signal pins.
Also replaced battery terminals with new ones along with cleaning and checking of grounds.

Appreciate your help Philly-R6

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