IGROWL

So the Black 944 suddenly stopped running the other day on the way to work. I pulled off to the side of the road and tried to restart. It took two times turning the key with no cranking or any sound at all but the third try it started right up like normal. Ran down the list in my mind of the things I am going to have to look at when I get home tonight. Of course I want to start with the easy things to check first.

DME relay at the top of list. I pulled it and replaced it with a new one that I bought a while ago knowing that this would possibly be a problem one day.

Does this look normal there looks like burn marks on the metal. I pulled the one from the Red 944 and it is clean looking with no marks at all on the metal.

John_AZ

Higher resistance causes overheating.
Dirty contacts on the relay or the connection. Corroded wires.

Clean all contacts around the DME/fuel pump relay.

Clean the fuse panel and fuse that is on the circuit.

Pull the voltage regulator and check to see if the carbon contacts are worn. If shorter than 5/16" replace. If one leg is shorter, you have to polish/lathe the slip ring or you will ruin the contacts on a new VR

Clean the battery posts.
If you have battery acid corrosion on the battery cables by the post connections you should replace the battery cable with a better--thicker cable with more strands. Do not buy a set from an autoparts store. They are crap and not the correct guage for our cars.

Run a second thick negative ground wire to the block.

OR
Just replace the relay until it happens again.

GL
John

IGROWL

Thanks John for all your help.

I was hoping for a easier solution but when does that happen with these cars.

I think I will check the new relay every week and see if any marks start to show. If they do it's time to take the steps you suggest.

IGROWL

Just wanted to let everyone know that the DME relay did not fix this problem. Tried to take the car out tonight for the first time since I changed the DME relay. Now I can't get it to run more than a minute and it stalls out. I had to push it back down my road to get it back home.

xsboost90

if the pump is starting to lock up it will pull more resistance through the relay, causing the relay to burn.

IGROWL

Well it turned out the fuel pump was fine. The culprit was the ignition coil.

I am going to keep a eye on those DME tabs.

Thanks to everyone for your help and ideas.