Cold Start DME Relay Related Problem

[kbrockman]

I have a 1986 Porsche 944 Turbo and am having troubles starting and running the car in the morning when it is cold out. In the afternoon however, the car starts and runs great.

The symptoms are a terrible stumble in the engine, sometimes stalling it, and sometimes making it unable to restart. The stumble often occurs when I start the car, hit a bump in the road, or even go to push the clutch in or let it out. Sometimes I can start the car in neutral (with the clutch in or out) and then when I go to push the clutch in (or let it out) the engine dies.

I am fairly sure that the problem is in someway related to the DME relay for a couple of reasons. First, if I get the car started in the morning when it is cold, but have it sitting in neutral, I can tap heavily on the DME relay and the car stumbles lightly (dropping the tach to 400 or 500 RPMs before returning to regular idle). Additionally, I have been able to create a temporary fix to the morning cold start problem by manufacturing a copper jumper to replace the DME relay (putting it in right before I start the car and taking it out as soon as I reach my destination and turn the car off). With the jumper in instead of the DME relay, the car runs great with absolutely no stumble and no problems.

I first thought that I had a bad DME relay so I tried replacing it with another spare I keep on hand. This didn't solve the problem though. Unless I have two faulty DME relays, the problem is something else that affects the DME relay.

[GrantM951]

You can try replacing the DME temp sensor, it's about $20 and solved my cold start problems.