924Board.org

[Josh]

hi
Ive had my 924 turbo for about 6 months now, and i hadnt really noticed the high idle untill recently as it seams to be getting worse.
The car starts easily when cold and will idle at 1000rpm no problem on start, however after about 5 to 10 minutes the revs slowly start to creep up to around 2000rpm sometimes as high as 3000.

I checked my air intake lines and found a huge tear in my one rubber inlet tube just after the mass flow metre before goes onto the turbo, replaced that quickly in hopes that that would solve the problem, no luck, i then read that a stuck AAR could result in a high idle if stuck open, hoping that that could be the problem did all the checks to find mine is working perfectly.

i have read hundreds of older posts (litrally hours of reading) but havent found many people with the same problem. a few 944 owners have experienced the same problem but the posts never seam to come up with a solution

Please if any one can help it would really be appreciated!!

[Grenadiers]

What year is your car? The '80 cars have the oval-shaped upper charge tube attachment, which can work loose. '81-'82 cars have round ones. The latter has an orange o-ring that can flatten over time. Sounds like something is opening up as the engine warms. Check all rubber elbows for cracks/air leaks. The POV at the turbo can lose it's two gaskets. Happened to my '81 car, I could hear a whistling noise. If your car is running lean, you'll see that the exhaust manifold will get red hot as a result. Have you messed with idle air screw on the throttle body?
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

[Josh]

My car is a 82 model. I dont think the POV (pop off valves? ) would be an issue as the car boosts perfectly, i have an aftermarket boost gauge installed. i havent touched the idle screw, but could be a possibility that the previous owners have? but it idles perfectly between 900 and 1000 on start up and then it varies between 2000 and 3000 when hot, if the idle screw was an issue wouldnt it always sit at ether 2000 or 3000 ? sorry for all the questions, its just im still quiet new to the turbo car. im going to give the elbows another run through to check for cracks, i really hope i find one with a massive hole that sorts the problem out!! as i have spend hours searching the car for possible causes.

Thanks so much!

[Josh]

ive checked all 5 elbows and they were all in not too bad condition with no major cracks that could have caused a leak, did pressure tests on them to make sure.

if the high idle is caused by the car running too rich, then is the likely cause an air leak somewhere after the mass air flow metre and the throttle body, so its not getting the correct amount of air into the throttle body for the amount of fuel going through?

[pelican13]

After checking my documents it seems that if the throttle body contactor is disconnected or bent, the iddle is very high.
And read the post "copy of the 937 DITC unit" ,one of the last posts of Macgyver show a copy of the 931ignition.If you succeed to read it ,there is a lot of informations to solve your problem.

[Josh]

by throttle body contactor do you mean TPS (throttle position sensor)? As I removed my TPS and found out that when my throttle was closed it wasn't engaging the micro switch inside the TPS so i reset it so that there is now a distinct "click" when the throttle is pressed, however that hasn't solved the problem, if anything my problem has gotten worse as the car now spikes to 3000rpm
_________________
Porsche 924 turbo 82
Alfa gtv 2L 83 (sold)
Suzuki SJ410 (sold)
three awesome cars and still under the age of 21

[Rasta Monsta]

Bad AAV? I would pull it, give it a good dousing with TB cleaner, then do the freezer test on it to make sure it is functioning.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Josh]

ive tested my AAR and its working, closing when warm and opening when cold, i read an older post of a 931 with very similar symtoms as my car but cant seam to find the post again.
it suggested disconnecting the disconnecting the ITS ( intake temperature switch) i did this and straight away the revs dropped from 3000 to 900?? i took it for a drive and for the 1st time in months my car idle at 900 at a traffic light, almost tears of joy!

but now my problem is... what is the ITS? what does it do? my cars revs still linger a lil when my foot is on the clutch but slowly drop back down, so could that be a faulty Decel valve? as mine filled with water from my water injection kit.
_________________
Porsche 924 turbo 82
Alfa gtv 2L 83 (sold)
Suzuki SJ410 (sold)
three awesome cars and still under the age of 21

[Grenadiers]

Mine did the same 3 years ago, I'd unplug the air temp switch, and rpms would drop. I still had not figured out where the vacuum leak was. Me thinks you need to keep looking as well. The two gaskets on the POV had disintegrated on my car, and the leak ended up being there. The car still ran like a scalded dog, so, the POV is still working. I'd give that a shot, warm up the car, and get under the front and listen. The frame-side gasket is the hardest to replace, you could unbolt the other side to check that one first.
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

[Josh]

so you suggest the problem still lies with a vacuum leak? unfortunately ive run out of time for working on the car as my holiday is finished and i have to drive the car 700km to varsity. i think il change the POV gaskets next holiday then, but is it ok to run the car with the ITS unplugged as it solved the problem for now?
_________________
Porsche 924 turbo 82
Alfa gtv 2L 83 (sold)
Suzuki SJ410 (sold)
three awesome cars and still under the age of 21

[Grenadiers]

If you getting a lean situation, then no. After running the car up and down the roads, have you noticed if the exhaust manifold gets red-hot?
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

[Josh]

no the exhaust manifold gets very hot but never quiet seen it turning red hot, but will take it for a spin to double check, thanks so much for the help!
_________________
Porsche 924 turbo 82
Alfa gtv 2L 83 (sold)
Suzuki SJ410 (sold)
three awesome cars and still under the age of 21

[Josh]

i see now what you mean about the car running like a scalded dog, huge drop in power since removing the ITS
_________________
Porsche 924 turbo 82
Alfa gtv 2L 83 (sold)
Suzuki SJ410 (sold)
three awesome cars and still under the age of 21