best 944 turbo

86 944 turbo has recently become a daily driver. Only 67K miles - runs great (only previous owner was a relative who babied it). I'm not tremendously knowledgable but recently after topping off the coolant tank (no prior problems with overheat) the car suddenly starts up very strong and idles at 1500 dropping off to 1000 in a cyclical manner. Previously it idled at 800-900 rpm. What's wrong?? Any suggestions greatly appreciated. Thanks.

fletch.

You probably have a bad idle control valve, it's very common and a real drag to replace. If you look under your intake you will see it. The hose coming off the passenger side of the intake (the middle one) is connected to it.

Intakes gotta come off, to do it.

Skip

Throttle Position Switch...

Check to be sure you didn't knock the connector loose whilst wrestling with the cooling system. Could also be end-of-life. The TPS microswitch is a common failure point, but is not serviceable. There is an adjustment technique in which you would loosen the phillips screws and adjust the microswitch (audible) to make contact at close-throttle. A replacement unit is ~$50.

If the TPS does not send a "closed" signal to the DME, it will continuously hunt for idle speed. The idle stabilizer usually gets stuck closed if it fails, which causes low idle (~600rpm)

A very rare failure mode that causes the same thing is the DME itself (pin 31 0r 33, can't remember)... though I had this happen to me... I'd call it a fluke and caused more by the previous engine fire

Here's a pic similar to your setup:


Good Luck!

[ 06-20-2001: Message edited by: Skip ]

aka 951

Skip's probably right - those are classic TPS symptoms. Check it out with an ohm meter and listen for a "click" when returning to idle. If no click, you may have been lucky and the switch could merely be out of alignment.

Erick

best 944 turbo

Thanks for the advice all. However, I have some sudden and sad news to report. When I took the car to my mechanic, the symptoms suddenly stopped, and no work was needed. However, today - three days later - for reasons still unknown my loved 944T CAUGHT ON FIRE. After exiting off of 30 mi. of highway, I heard a pop and white smoke appeared. I pulled off, and within 15 min. the engine compartment was engulfed in flames. Needless to say it was a total loss. One fellow 951 driver passing by was fortunate (or unfortunate) to have seen the whole thing.
I will miss being part of this community. My 951 had tremendous sentimental value. The original and only other owner was my father who kept it in great shape before handing it to me. There is one less 86 951 out there today - making yours that much more valuable.

Still in shock - formerly "best 944 turbo"