1990 C/4 shuts down intermittently
 

Problem: Driving along (can be stop/go traffic or 55-60 mph hway driving) engine will either stumble or will just die. The symptoms are as if either fuel or power was turned off. Also, this can happen when the engine is cold or warmed up, at any speed, and can happen every day, can happen after a couple of days, weeks or month. Although lately it's happening every day.

When it dies, I can usually start it right away or I have to wait about 5 minutes and then on to the next occurrence.

Here's what's been done so far: Replaced fuel pump. Replaced fuel filter. Inspected/cleaned filter inside gas tank. Replaced DME (fuel pump relay (twice). Replaced flywheel sensor. Inspected/swapped ignition coils. Replaced distributor caps and rotors. Replaced secondary distributor drive belt. Blew-out fuel line and return. Inspected all motor cabling and computer (DME) connections.

Can anyone offer further insight???

I had the same problem earlier this year, (90 C2). Replaced the DME relay that's in the fuse compartment. The original will have a 944 prefix on the top. The new one starts with 993 I believe, and it's a little taller. That did it.

I have read a post similar to this, but it was during the rain that the car was affected. It ended up being the oxygen sensor. Its cheap, worth a try?

I do not beleive the O2 sensor can stop the car unlessanyone can dispute this!.
However, You may wish to follow my sorry thread which may give some help
rgds Ben

The O2 sensor was shutting down my C4 most likely. All of a sudden it would run so rich that flames would shoot out the exhaust and it would stall. I replaced the temp sensor and the 02 sensor had to be reset.

Ideally, go to a shop with a Bosch Hammer to read out fault codes.

If you can't do that, you could try re-setting all the various control units by disconnecting then reconnecting the battery. If you want to re-set just the DME, turn the ignition on but do not start the car. Put your foot on the gas pedal, and hold it to the floor for more than 11 seconds. Note that if you do either of these procedures you will clear fault codes.

Based on other 964 owners' experiences, also carefully check battery ground strap and the two vacuum switches on top of the throttle. Good luck and let us know the outcome.

--Bob D.
'92 C2


[This message has been edited by rdvnac (edited 06-05-2001).]