I have an 83 944. first thing in tha am. car starts and runs fine for 30 seconds, 30 minutes, doesn't matter, still runs great, but turn it off, and will not start again till next day. even if it's only run for 30 seconds.

 

Start by replacing your DME relay. It will get hot, and the contacts will spread until it cools down.

If that doesn't work, then start looking at your speed and reference sensors, the wires will be affected by the heat in the same way. The 20 year old wiring harness is usually cracked and brittle.

 

Thank you,
I've already replaced the speed sensor, but not the reference sensor, and I went to pelican, but I can't find a listing for the DME, and don't know what the acronym stands for. Now this morning it would only start if I held the throttle to the floor and cranked for about 20 seconds. Then it lets out a huge plume of black smoke and stinks like fuel, but I checked the ignition, and the spark is strong. Please advise when you have time

 

Ifound the DME relay, but that was the first thing that I went after. There just seems to be no telling when it is going to run, but when it does, it sure does nicelly

 

I am seeing the engine wiring harness at the speed and reference sensor connectors fail on these cars at an alarming rate. The wires get brittle, insulation cracks, and when they get hot, then the car refuses to start. Lindsey racing makes a replacement harness for those two sensors which is then wired back to the DME. That way you don't have to replace the entire harness (which is pointless anyway, since a used harness will do the same thing eventually, and a new harness is about $2k).