mavfan

Durring winter when its cold my car is normal, so i havn't even thought about this... But today it was warm outside and the problem, where my car will idle at 2k randomly, came up again. Even when i'm trying to slow down below 2k, the car will be fighting me to stay up past 2k... So what needs fixing?
Video of my car being lame...
also in the vid my car is sitting still the whole time, meh

Airflite40

The throttle cable on mine sometimes gets caught on something and it wants to idle at 2500.

When its idling like that can you open the hood and try to push the throttle "closed" see if the cable is stuck.

mavfan

when the problem first started i thought this, but it only happens when its warm out, say 40+ degrees. before winter i was having this problem, durring winter i was not and now its warm and i'm having the problem again.

xsboost90

could be the idle stablilzer valve thingy? - erins car's throttle cable came off some and got caught on the throttle cam the other day. Idle stuck at 3k luckily she was behind me and i stuck the cable back on there all the way and tightened the cable alittle.

mavfan

it can't be the throttle cable catching on the throttle cam, right now its got the 1:1 ratio throttle cam on their without the arm so there'd be nothing to catch onto. and i've swapped the old and new cam back and forth and they have no effect. only the warm weather.

J Silverman

My car does the same thing in the summer. I asked the shop that does all the work I cant DIY (it helps that they build and race 944s) and they told me that its most likely the idle stabilization valve. I asked them if it could be the TPS and they said yes but that it was unlikely. The porsche gods will probably strike me down for saying this but the procedure for testing the ISV seems very straighforward. From Clark's Garage :
"Clamp line from Idle Stabilizer / Auxiliary Air Valve to the intake manifold to see if idle stabilizes. If it does remove the Idle Stabilizer / Auxiliary Air Valve, clean it with Carburetor and Choke cleaner, reinstall and check operation. If the surging idle persists, replace the Idle Stabilizer / Auxiliary Air Valve. "

mavfan

i checked clarsk-garage and they had information about the idle speed adjustment, but i couldn't find the idle stabilizer valve or auxilar air valve. could you point me in the right direction? i'm guessing that its on the throttle body? should i just start spraying things out in there? in the J boot there is a good sized hose that always filles up with oil. but i thought that was for the oil/air separator.

mavfan

i'm guessing that it would be the AAV since the problem is on my 88 924S and i'm guessing that it still uses the old valve correct?

mavfan

why the hell does it cost $170......... anyone on here have a good used ISV?!! lol

edit: hey they have rebuilt ones for 80.00

mavfan

did you clean out your ISV and did it help?

edit: also i may be wrong, but it looks like in this diagram from clarks-garage, that the ISV is located under the J boot. Am i wrong?

mavfan

meh i dont want to take off the intake...................................... i wonder if i could reach under and pull off the two hoses to start attacking it with carburator cleaner!!!

btw thanks for the pic, finally i understand where and what you guys are talking about!

EMBPilot

if you think its the ISV, just pull the intake manifold and start replacing whatever you can get to under there while its off. it looks intimidating but its not. another culprit may be your DME temp sensor. which is also easy to get to when the intake is off. my car was down for about a week as i slowly did this project. Buy new hose clamps, and rubber hoses, some you need to get online some you can get from local auto parts stores. Im a newbie, and this was one of the most rewarding projects ive done on the car. It idles much smoother now and no longer has a mind of its own when sitting in the garage warming up.

My car used to, infrequently, while at stops, come down from RPM and stop at 1500-1800 then SLLLLoooowly come to idle. but it also used to hunt like mad when it was warming up, 850 to 1100. since doing this project, replacing the vac lines, new ISV, new temp sensor, cleaning injectors and a few other odds and ends, it hasnt repeated any of this behavior.

http://forums.pelicanparts.com/showt...hreadid=325124

xsboost90

i should have one from an 87 924s if you need it...have to double check though.

EMBPilot

taking the intake manifold off is simple, but a bit tedious, going through all the trouble you may just want to assure you have a perfectly working ISV in there that will give you years of headache free service... its the only expensive part that this project really entails. for 180 bones it may be worth the good nights sleep you'll get