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craigmk2vr

Vr lumpy idle on cold start

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Hi all 

 

been on the site for many years now but normally find my answers by searching so don’t tend to post much 

 

i have a mk2 vr that idles like s4it from a cold start , it’s perfect after a minute of holding it at 1000ish rpm my old mans mk2 vr Jetta has high idle when starting from cold but mine just hunts and cuts out 

 

engine is obd1 converted to  obd2 problem was present before converting too 

 

so far I’ve replaced the following (not to rectify fault ) 

 

fusebox to engine loom 

engine loom

coil pack

maf

plugs

ecu

blue temp sensor 

throttle body

inlet mani 

 

Car runs fine once it’s warm and absolutely flys 

 

Any help would be much appreciated 

 

no codes showing on reader 

 

thanks 

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Have you looked at the PCV VALVE? Over time can get filled with sludge and dirt. This can cause the valve to become blocked and inoperative, or it may start to leak. A PCV valve leak can cause the air-fuel mixture to run too lean, and this will cause a rough idle from cold. I've deleted mine as they are more trouble than there worth. Let me know how you get on.

Hi all 
 
been on the site for many years now but normally find my answers by searching so don’t tend to post much 
 
i have a mk2 vr that idles like s4it from a cold start , it’s perfect after a minute of holding it at 1000ish rpm my old mans mk2 vr Jetta has high idle when starting from cold but mine just hunts and cuts out 
 
engine is obd1 converted to  obd2 problem was present before converting too 
 
so far I’ve replaced the following (not to rectify fault ) 
 
fusebox to engine loom 
engine loom
coil pack
maf
plugs
ecu
blue temp sensor 
throttle body
inlet mani 
 
Car runs fine once it’s warm and absolutely flys 
 
Any help would be much appreciated 
 
no codes showing on reader 
 
thanks 

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Haha. Ok cool. Whip the breather filter off mate and check it's not blocked. That's if it's been on there a while.

Hi 
 
Forgot to mention pcv has gone and breather filter in place , also running a catch can , thanks for the shout though , 

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Idle control valve ? That’s built in on the obd2  throttle body ain’t it ? I’m baffled by it if I’m honest as the common things have all been done and some , what I really don’t understand is that even with the obd1 to 2 swap the problem is still there , the engine was stripped down to a bare block and re build last year with all new sensors crack pipe stat etc etc 

 

i thought maybe a broken wire in the loom but then again the looms been replaced too , 

 

its off to see vince next Saturday for cams and a map so hopefully he will be able to suss it out let’s be honest if he can’t I’ve got no chance 😂

 

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Yes idle control valve pal. I thought it was a bolt on next to the throttle body on a obd2? I could be wrong. Mate..... it's doing my head in and it's not even my car. . Yes I'm sure Vince will get to the bottom of it. Keep us posted what the problem was then I can get a good nights sleep. Hahahaha

Idle control valve ? That’s built in on the obd2  throttle body ain’t it ? I’m baffled by it if I’m honest as the common things have all been done and some , what I really don’t understand is that even with the obd1 to 2 swap the problem is still there , the engine was stripped down to a bare block and re build last year with all new sensors crack pipe stat etc etc 
 
i thought maybe a broken wire in the loom but then again the looms been replaced too , 
 
its off to see vince next Saturday for cams and a map so hopefully he will be able to suss it out let’s be honest if he can’t I’ve got no chance
 

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Right had it plugged in again and it’s showing fault code 00282 changed throttle body for a known good one and still the same so thinking it’s a wiring issue , will investigate when it comes back from Vince and update on the cause , 👍🏻👍🏻

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When you changed the throttle body did you use vag com to test and reset? Sounds like throttle position actuator needs resetting. You need to do a throttle adaptation, this runs the throttle body through a test and allows it to reset itself. as far as im aware the only way to do this is with vag com. its dead easy to do but there must be no other faults before you do it.

Right had it plugged in again and it’s showing fault code 00282 changed throttle body for a known good one and still the same so thinking it’s a wiring issue , will investigate when it comes back from Vince and update on the cause ,

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turns out the obd2 ecu I purchased was faulty , Vince replaced my ecu and all is good with the starting etc 

 

now ive just got an intermittent misfire so going down the coilpack route , new coilpack fitted March 2018 but only a £60 eBay one , 

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