High Idle when cold

[joobienooner]

I've gotta 91 TSi, I was driving and I let off the gas and put the car in nuetral at a stop light and the car stalled. I started the car up and it immediately stalled again, to keep the car running I had to keep my foot on the gas. When i got home i turned the idle screw up until it would idle at 800rpm. But now when I do a cold start the car idles at 2000rpm until it warms up a little and it slowly goes down to ~800rpm. What do you guys think the problem could be? Thanks in advance.

 

[bastard dsm]

common prob. with the TB,their is a fix for that on vfaq if im not mistaken.

 

[MrBoxx]

You have a Fast Idle Air Valve that artificially keeps idle high to warm the car up faster. When the temp of the FIAV goes up, the throttle plate closes until you get normal idle, which is about 800. Perfectly normal.

 

[montuner]

i got a 92 tsi and when i drive my ish cold it ALWAYS revs high at a stop sign, then drops down about 10-15 seconds later to 7500 rpms an its fine, but it does that till it gets warm...

 

[Bud92gsx]

Ya know that is really a commom problem. if ## IAC was bad it really wouldnt isl at all, well at least thats what ive found soo far. Check vfaQ or search dsm.

 

[jake7420]

it probably is your iac. try checking inputs and outputs to and from the pcm. try and find a scantool to put on and watch the counts as it trys to adjust, might be able to actually figure it out then just do some ghetto trick to cover it up

 

[talintidturbo91]

i heard that a malfunctioning egr would do that too.

 

[90GSTBoosted]

A few things would do that along with a perfectly functioning car. Every car warms up faster this way but if it keeps doing it even after it warms up then it's a problem.

 

[JayRolla]

You have a Fast Idle Air Valve that artificially keeps idle high to warm the car up faster. When the temp of the FIAV goes up, the throttle plate closes until you get normal idle, which is about 800. Perfectly normal.

It should idle around 1500 not 2000rpm. I have the same issue and its so annoying. I know my throttle body is messed up and I will be replacing it soon. It has all types of idle issues.

 

[90GSTBoosted]

Mine started doing it out of nowhere for no reason and after no work being done on the car.

 

[meliketoball]

Its totally fine, its supposed to idle high when its started cold like what Mr.Boxxx said.

 

[Steelnation36]

yea itll idle high especially in the cold when its started up i usually start it up like 5-10min before i leave the house just to let it warm up... i actually start it up for a short time before driving in any condition but thats me

 

[JayRolla]

yea itll idle high especially in the cold when its started up i usually start it up like 5-10min before i leave the house just to let it warm up... i actually start it up for a short time before driving in any condition but thats me

Not at 2000rpm though. Ive owned three dsm's and they didnt idle that high when warming up, or do any of my buddys cars. When my idle was working correctly I would idle up to about 1600rpm max. Now it goes up to 2000rpm and is way annoying.

 

[Dsm2nr89]

Same here. Last year i had a 91 tsi awd and it would idle in cold starts between 1500-2000k rpm until finally coming down to 800rpm. I had a bad "biss" but regardless i changed my pcv valve and thermostat and that a world of a difference, car never idled super high again since then.

 

[ranger2339]

Were is the PCV valve on these cars? My car has a bit studder/low idle (like 5-700) when its cold, untill it gets a bit warm, then its fine.
Man these cars have some major issues.


Josh

 

[snowborder714]

Were is the PCV valve on these cars?

http://members.shaw.ca/dsm.1000q/Engineprimer/2G/pcv.htm