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High idle at startup

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When I start the car the revs quickly climb to just under 2000 and stay that way until the car is really warm then settles to 1000. When it's idling high I can completely lift off both clutch and accelerator at the point when it would normally stall, it rolls forward.

Does anyone recognise this problem? I assume it must be cold start or warm up of some sort, it does have the Audi throttle body and warm up valve conversion, is it likely to be that?

Thanks in advance

Simon

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I also have a rev counter which seems to just die now and again, needle drops to zero then back up, is this an electrical fault? Thanks!

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Sorry moderators - this should be in Big Block injection engines - can you move please? Thanks

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to start with i would go over all the basic kjet tests, as per this thread:
http://www.clubgti.com/showthread.php?195423

and this thread has 8v timing marker pictures:
http://www.clubgti.com/showthread.php?124949

just ignore the 16v parts and the digifant 8v setup procedures. for kjet ignition timing you do that at idle with vac line to dizzy disconnected and plugged, the timing marker on flywheel is the same. For idle and co this is just done at idle, the info about the breather pipe disconnection does apply, but if its really clean then you probably wont notice any CO difference caused by the breather gasses.

the throttle screw orign is worth changing, i bought a big box of generic orings and used the closest size on mine.

in addition look at your AAV, make sure it has a good 12v feed when the engine is running. there is also a Y piece somewhere which has a valve inside that can leak? you can try clamping the air pipe to the inlet manifold see if that drops the idle

Hello my name is John and I'm a dub addict.



My wiring diagrams and other documents have moved here:

VAG Documents & Downloads

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Thanks very much rubjohnny - that is pretty much exactly the info I needed, you're a great asset to this forum.

I'll see how I get on but your useful knowledge is much appreciated.

My question wasn't even in the right section!

Thanks!

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Replaced all my hoses with the fabric braid round the manifiold and dizzy, made no difference, if anything the cold idle is higher now, (about 2000 rpm) it then dips as soon as I lift off the clutch, even just a little bit.

Is this all pointing to the AAC?

Thanks

Simon

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what happens if you try to lower the idle with the screw, or is it already all the way in?

Hello my name is John and I'm a dub addict.



My wiring diagrams and other documents have moved here:

VAG Documents & Downloads

You'll need to sign into google/gmail for the link to work! (its free!)

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Good question as the problem is only cold idle, once it's warmed up it drops back down to 1000 rpm, same as when I lift off the clutch. It then creeps back up (not slowly though!)

Thanks for your help again dude

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Going to try this anyway obviously...

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Hi simon.
My car is doing exactly the same😟 replaced new vacuum hoses & she races up to around 2k on cold.
& I can't suss it out😕😕

What was your outcome???

Many thanks
Mark
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