I have an '84 944 Porsche. I've had it for almost two years and it sat for atleast two years before I got it. When I got it it would stay running for about a minute and then it would shut off. If you waited 30 seconds, it would crank back up run for a minute and shut off. About three weeks ago I decided to take it to a shop that works on foreign cars and claims they have a lot of experience with 944's. Initially they put a fuel pump on it, new battery, new gas and an alternator belt. They told me at this point it was running good and would not shut off on them. It sat for the weekend and then Monday it was back to its old tricks (shutting off again). We went by the shop to check on the car and they showed us how they figured out if you unplug one of the injectors the car stays running. They suggested that it could be a control unit or a wiring problem. They felt more confident it was the control unit so we went with it. They ordered a used control unit and it is still in the same shape. Now they are suggesting a ping test to find the problem wire. Does anybody have any suggestions? I am up to a $1000 dollar bill with this mechanic and it seems like they don't have a clue.

 

Bad fuel pressure regulator.

 

Thank you for the reply. I talked to the mechanic and he says the fuel pump is maintaining 32psi. He says they are losing signal to two injectors. He says they have an intermittent injector pulse. Any more suggestions?

 

Then i would look at the speed and reference sensor wires at the harness at the fuel pump/dme relay

 

Just posting a follow up in case it helps someone else. The '84Porsche 944 is running after approximately six months in the shop. The final outcome was two bad crankshaft sensors and fuel pressure regulator. The control unit was not bad. It stays running now. I just need some work on the clutch and cooling fan, but I have been able to drive it and it is awesome!!!