My 95Tsi barely idles when cold

[93MR-2Turbo]

Ok when i start the car when it's cold or even somewhat warm ( it's worse when it's al the way cold though ) it wants to die right away, so i put my foot on the gas to bring the rpm's up to just under 2k. the rpm's will drop down to almost 100 and surge up to 500 if i don't give it some throtle. also the car seems to have a misfire ( the CEL has throne that code once ) under 1200 rpm's ( the lower rps's the worse ) but it clears up alot when the car is fully warmed up
I've described the problem in as much detail as possible without being too lenghty, does anyone know how to diagnois this idle problem?

 

[93MR-2Turbo]

anyone had this problem before?

 

[oddrob]

my car has a hop problem, maybe we can get them together for a beer.

 

[93MR-2Turbo]

anyone else?

 

[oddrob]

Sorry had to do it. Idle is controlled by various things. Does it idle properly when warmed up? It could be your coolant temp sensor. You can check your idle control motor with a multimeter, that may tell you right there. Is your coolant still routed into your throttle body? It may be the thermo valve. Does it seem to be excessivly rich at idle?

 

[93MR-2Turbo]

it doesn't run rich at idle, and my interior guage for coolant temp works fine. Is there another temperature switch for the ecu?
I have not yet checked the idle control motor, and the previous owner payed some "DSM guru" ( self proclaimed and an idiot because i know the guy ) to istall a new throttle body so i'll have to examin that tomorrow to see if the coolant line has been altered.
Thanks for the suggestions and BTW what is a thermo valve?

 

[adam355]

Exact same problem on my car been trying to figure it out for almost a year now. I'v run seafoam to clean out my throttle body and my isc tested good, no luck. Yes there is a different coolant temp sensor that goes straight to the ecu, my coolant temp sensor readings show up on my logger so I figured the sensor was fine, but I should prolly test it yet. I also have 10-15 for vacuum readings at idle, so I might have a boost leak thats causing it.

With idle situations like we are having a bad isc or fiav isn't looking like the answer to our problem. I'm starting to lean towards it being a boost leak and as soon as it gets warmer out I am going to do a more efficient leak test. We should keep this thread going though with eachother posting any progress.

 

[93MR-2Turbo]

Exact same problem on my car been trying to figure it out for almost a year now. I'v run seafoam to clean out my throttle body and my isc tested good, no luck. Yes there is a different coolant temp sensor that goes straight to the ecu, my coolant temp sensor readings show up on my logger so I figured the sensor was fine, but I should prolly test it yet. I also have 10-15 for vacuum readings at idle, so I might have a boost leak thats causing it.

With idle situations like we are having a bad isc or fiav isn't looking like the answer to our problem. I'm starting to lean towards it being a boost leak and as soon as it gets warmer out I am going to do a more efficient leak test. We should keep this thread going though with eachother posting any progress.

Defidently a good idea, and tomorrow (Saturday) i will be checking all of my IC pipes for leaks and maybe i'll pull the IC off and clean it.
Also i am running 18-20 vacume when the car is fully warmed up so you could very likely have a boost leak. I need to borrow my fiends DSM link and find out what my temp sensor is reading.
Keep the updates comming.

 

[93MR-2Turbo]

I just cleaned my IC ( with gasoline ) and it looks band new inside! It wasn't that bad but i just wanted to take care of it for "peace of mind" I'm thinking about just buying a coolant temp sensor to see if that works.

 

[adam355]

I just cleaned my IC ( with gasoline ) and it looks band new inside! It wasn't that bad but i just wanted to take care of it for "peace of mind" I'm thinking about just buying a coolant temp sensor to see if that works.

Well make sure you update me once you do.

 

[wing91]

I have been having the same sort of problem with my 97 gst. It is running rich at idle though or so I think. I have check everything I can think of. I been over every sensor except the knock positioning sensor and taken all the mods of trying to fix the problem. The only thing left on the car is a hks filter. The car idles in between 100 to 500 almost like it is missing. I have changed plugs, wires, coil packs, and test for vacum leaks although not sure if my method was that good. I hooked up a compressor up the the turbo on the intake side while spraying fluid over every vacum line I could get to looking for bubbles and listening for air. If you guys have any luck I would be interested to know I have been dealing with this in my spare time for months. Hope I didn't leave anything out.
Thanks

 

[wing91]

O'yeah it seems to run alot better at high rpms and I changed the tps but when you go to shift it looses power agian and has to build back up.

 

[93MR-2Turbo]

Just checked my ISC today and circuits 2-3 and 4-5 were ok the others showed no resistance or very low. So my ISC is defidently bad. I'm pretty sure but not positive that it would be causing my cold start not to work. My idle stop screw was out of adjustment (idiot who installed the new throttle body before i got the car) and the throttle cable was just alittle to tight causing my inconsistant idle speeds.
Also adam i have a misfire (cylinder no. 3) and have had it since i got the car a few weeks ago. Hopefully in a few days i'll have time to check my temp sensors.

 

[93MR-2Turbo]

I have been having the same sort of problem with my 97 gst. It is running rich at idle though or so I think. I have check everything I can think of. I been over every sensor except the knock positioning sensor and taken all the mods of trying to fix the problem. The only thing left on the car is a hks filter. The car idles in between 100 to 500 almost like it is missing. I have changed plugs, wires, coil packs, and test for vacum leaks although not sure if my method was that good. I hooked up a compressor up the the turbo on the intake side while spraying fluid over every vacum line I could get to looking for bubbles and listening for air. If you guys have any luck I would be interested to know I have been dealing with this in my spare time for months. Hope I didn't leave anything out.
Thanks

I know there is a little bead in the throttle body where the coolant lines run through it. That little bead shrinks or expands depending on coolant temp to induce more rpm's while the car is cold. this almost can't be my problem as i have a brand new throttle body from the dealer. I thought i would mention that because you hadn't covered that in your description.

 

[Defiant]

anyone had this problem before?

The one of threads being continually bumped? Yeah, despite the rules, we get it all the time.

Luckily, I know how to fix it.