Naysay

Hello and thanks to anyone ahead who helps with this problem.

I recently purchased a 1986 944 turbo S, about two months ago, and it has been running perfectly fine until today. I realize my mistake of not getting a PPI done but that's beside the point. I started down the road and my gauges all of a sudden started jumping around. My speedometer would drop to 0 and go back up and my tachometer would jump around. sometimes affecting the engine speed other times just the gauge. the windshield wipers also began to slow down and get stuck almost like they were losing power and at times the fans would cut off. When i turned around for home the throttle body seemed to be unresponsive at times. I would be giving the car gas and nothing would happen leading to it almost stalling out and occasionally it'd jump back to the normal speed. I tried to turn on my hazzards on the way home and they'd only work part of the time.

Me, my friend, and his family all seem to think it may be the ECU or a main fuse that's shorting but that's all we could come up with and I'd like to have some certainty on it before I make any expensive repairs. As I said before there were no previous indicators of electrical issues whatsoever. My radio would occasionally cut off and on but i wrote that off as being just a bad wiring job for it because it was an aftermarket unit. I would really appreciate any advice or help with this because i cannot think of anything else to explain this.

turbodave

Replace the ignition switch and go from there. After 27 years it's time. It will save you hours of trouble shooting. The DME must have a constant 12V. There is no main fuse, It's called the DME relay. You can replace this first but with the other associated failures I doubt this is your problem. Clarks Garage is an excellent reference if you don't have the factory manuals.

Yarf

Also clean and check the battery terminals and the ground connections from the negative terminal of the battery to the chassis and to the top of the bell housing at the back of the engine near the fire wall. You should also have the battery tested.

theiceman

You may also want to consider one of those voltmemters that plugs in to your lighter.. This is the perfect application for that .. When it starts acting up you can see what your voltage is doing .. sometimes it isnt a drop but more of a spike .. if the voltage is high for long enough you will see it .. if that in fact is the case it is Alternator time .. but first things first .. you have some good advice above .. expecially the ignition switch ..

Naysay

Thank both of you. I'll check out Clark's Garage now and work on cleaning the grounds. The terminals were just cleaned a few days ago and i'll have the battery tested asap. These problems only occur while driving, everything is fine while it's idling. I don't know if that means anything more than what's already been said or not.

Naysay

thank you as well theiceman, however now that I think about it the lighter has been malfunctioning slightly here within the last week or so. Whenever i have something plugged into it, it seems to lose power and regain it sporadically. I'm assuming this is probably related.

theiceman

dude id be starting there .. lol

87 944 C

torch it and run away

Mikes-951

Unfortunatly i have learned the hard way, CHECK THE GROUNDS