944S tach:RUDE awakening on the way home??

Panzer909 · Panzer909's Garage

So I'm tring to diagnose a high (about 1100) RPM problem in the garage on the 944S this week. I stupidly start Effing with the idle stop bolt on the throttle housing but "think" I put it back to normal. Start the car up, no change. In fact the RPM seems back to normal(?) Okay. problem fixed, right?

So I take the car out tonight which involves about 20min+ highway driving. I start pushing it and at about 3500rpm the car momentarily goes nuts. It stumbles enough at speed that my head almost slams into the steering wheel and the tach wildly flies all over the place....then its back to normal. WTF? Should I re-adjust the idle stop screw? It never did this before. Perhaps I need to simply get the car out more often. Anyone ever have this experience before?

Steve Schubert · 02-03-2008, 02:31 AM

My car did that on the highway once. It did not stumble, it shut down for about a second then keep on going. It was the dme relay, the next time I drove the car it shut down on the highway. Replaced the relay everything was O.K.

968rz · 968rz's Garage

I think Steve is on the right track, that sounds like an electrical issue not a mechanical one. Plus it's ALWAYS a good idea to keep a DME relay in the glove box (it's cheap insurance),

hermesbooking · 02-03-2008, 06:15 AM

I now have an extra DME Relay in my glove box. Everyone has suggested it, had is sitting in the tool box of my car for several months, but now with some of the issues I have had with my car- Cheap Insurance!

procon · 02-03-2008, 06:29 AM

Sounds a lot like a problem I had with my 924, turned out to be the ignition control module.

Razorback1980 · Razorback1980's Garage

With the tach flying around like that...sounds like a coil issue to me as well. Open the hood at night and check for any sparks flying around. It may also do it more in wet weather.

968rz · 968rz's Garage

Quote:

Originally Posted by Razorback1980

With the tach flying around like that...sounds like a coil issue to me as well. Open the hood at night and check for any sparks flying around. It may also do it more in wet weather.

People think I'm crazy when I say this but, use a spray bottle with water and mist the elec system (watch for sparks as Razor said) I've done this for years as an auto tech.

1982911sc · 02-03-2008, 11:42 AM

My daily driver had a similar issue, it turns out the AC belt had rubbed through one of the plug wires..would only give me problems when wet. You could not tell the problem existed when it was dry..

Panzer909 · Panzer909's Garage

So I drove the car to work this morning and everything seemed fine. Didn't check for sparks under the hood yet, but I was thinking of something: Earlier in the day when this happened, I took the timing belt cover off to check the tension. In the process of yanking the top cover piece off, it was "hung up" by a white wire that sits near the distrubutor cap area. Its possible that I could have pulled or over-stretched this wire while fiddling to get the cover off? What does that wire do anyways? Don't have a pic at the moment.