A914MAN

Got my (new to me '91) 964 a couple weeks ago, made the 750 mile drive home without a hitch.

A few days after getting home got a benign CEL, next day no CEL no problem. Few days later, got the CEL on a short drive, turned the car off for an hour, no CEL on start up, drove a few miles got the CEL the engine cut out (misfire, stumble, whatever you want to call it) a couple times, cleared up no more CEL. When I say it cuts out and feels like it's going to die, car jack rabbits like you don't know how to drive a stick. Drove it an hour and a half later after 15 mins, CEL and it bucked several times, limped home with intermittent cutting out.

Now it tries to start idles roughly, then dies.

I tried to get the fault codes via the self diagnostic readout on the Durametric page, but never got a single fault code.

I'm starting with the typical: fuel pressure, fuel and air filters, voltage output, ground connections, electrical connections.

Does this sound familiar to anyone?

u7t2p7

Swap in a new DME relay; easy enough to rule out.

A914MAN

DME relay on the way

Jacke2c

When I first bought my car it had been sitting in a salvage yard for 2+ years. I got it cheap because no one could get it to run. Worked on it for a few days, bought a Durametric to diagnose and clear codes but still every week or so would do the same thing. I found that there are no less than a dozen different ground points that needed cleaning. I also found that bad (old) plug wires will on the odd occasion, misfire and give the same results... Finally many have reported about bad solder joints on the back of the clock. I wish you all the best, because when you get it sorted it will give you years of trouble free fun.

A914MAN

Relay has been replaced. I'm getting the 993 dual coil pack and two new custom coil/distributor wires from Kingsbourne Wire. Crossing my fingers this does the trick.

-nick

The relay won't trigger a cel, but is always good to have an extra. My go-to is the cht sensor. Test the resistance on the sensor. The spec is in the workshop manual, and has been posted here if you want to search.

Ken D

A914MAN

Thanks guys, I hope to work on it tomorrow afternoon.

A914MAN

Had a few mins to go over the easy stuff, and found out it's something in the second ignition. I unplugged the 2nd ignition module and it ran fine. Haven't had the time to do much else.

The 2nd coil is brand new. Caps and rotors are a couple years old (Beru) and I think I'm going to replace them.

Searching on how to test module

Jacke2c

That ties the two distributors together? If you take the caps off, you should be able to turn one slightly back and forth and see it move the other way approximately the same amount. Both shoul dbe linked by a belt in the body of the distributor.

A914MAN

Distributor drive belt seems OK, both rotors are turning and (without close scrutiny) seem to be in sync.

Since this problem cropped up just days before I got the car, and the "problem" coil was replaced. I'm thinking it's the module, or maybe distributor caps and rotors. I'm going to try and swap out the leads for the coils and modules first.

A914MAN

I carved out another 20 mins to do some more checking, and here's what I've found:

Dist 1 seems to run good with either coil, dist 2 won't run with either coil. It tries to start a little but won't run.

At this point I'm going to proceed with rotors and caps, as that seems the logical next step.