85.5 won't start

My 85.5 944 was working fine last sunday, then monday morning it wouldn't start. I played with it until wendsay when i got it to start once! After that it still won't start.
I've replaced the ignition coil, and checked the DME relay and think they are working fine. I've manage to trace the problem back to the ignision coil not getting a signal from the DME control Unit. I'm not getting a spark when it turns over. I get an initial spark when i first turn the key but then nothing after that. Could this be a DME Control Unit issue? Is there any way to test the control Unit? What else can I check before i have to bite the bullet and take it to a real mechanic?

Thanks
-Ted

Ted,

Check the speed and reference sensors. If one/both of these sensors is bad the car will not start. You can check the resistance of the sensors to see if they are good. They should be at approx 1100omhs. The sensors are located at the back of the engine near the flywheel. The plugs are just behind the air intake manifold. Infact a small brace that holds the plugs is attached to the back of the manifold. They are little rectangle plugs. A great sorce for info on 944 troubleshooting is clarksgarage.com

I have the same problem with my 87 944 and it was found that by tapping the ECU the car would start. I am in the process of having the ECU/DME control unit replaced.