DME Relay and spark
 

Does the DME Relay have anything to do with spark or ignition or is it just strictly a relay for the fuel pump?

I have a 1985.5 944 and am having some ignition/spark problems.
I have read a lot about the DME relay and how they go bad and cause starting issues and was getting ready to order a new one and on the description for the part it describes it as the "Fuel Pump Relay". Is there another DME relay that controls spark?
I have plenty of fuel but sometimes the car will start fine, other times there is no spark and it obviously won't start. When it does start, I can be driving down the road and then it just shuts down immediatley like I turned the ignition off. I replaced the 2 reference sensors on the bell housing a couple weeks ago. Thanks.

could be ignition switch as well.

clarks has a write up on testing the DME and symptoms of failure.

DME Relay Information and Testing

The relay also provides power to the DME, so it could be causing your problems. I'm kinda doubtful, but the relays are cheap enough and you should have a spare in your glovebox anyway, so you might as well order one. I'd check your wires and grounds too. Mine did something like that because some idiot (me) didn't have the negative battery terminal tight enough. It was tight, but just not tight enough. These cars are really sensitive to ground/electrical issues. That fix is cheap and easy, before you tear into something more expensive and time consuming.

Does the car have a factory alarm system?

yes, it does have a factory alarm.

Loose alarm connections, defective ign switch or it's loose connector, loose connections on coil, and always carry a couple of DME relays. They're cheap and when one goes Pfffft, you won't be stranded.

The alarm can de-power the DME (via the DMA Relay) and shut down the car. There is a simple procedure to bypass the alarm: Search Clarks Garage for "alarm". There are a number of ways that the alarm system can intermittently fail and cause problems. I once had a pin-hole sized perforation in the battery compartment on my 951 leak down onto the alarm controller (it's under the passenger footwell with the DME and KLR) and cause start/run problems. I replaced the controller with a salvaged one but now carry a couple of leads to bypass it with me these days.

This may well not be what is happening to yours, but it is an easy one to test.