No start

[wwells7]

I'm hoping you guys can help. I've got a 1989 944s2 that didn't have injector pulse. I have changed the dme and went ahead and out a new dme relay in because I saw some corrosion on it. I have good spark and do have injector pulse. I is very weak though. I'm using a noid light and the first couple of pulses are bright and then they turn very dim. Based on the wiring diagram the dme grounds all the injectors(fires them)at the same time on this car. The car does run on injector cleaner. I grounded the body of the dme with jumper connectors since I don't have it mounted but no change. This forum has given me a wealth of information in the past and I hope you guys can help me now. Thanks to all and have a great weekend!

[Pauld_94S2]

Congrats on the S2!

That your S2 will start and run on external fuel fluid is a good sign that almost everything is working. BTW, you can use gasoline in a spray bottle to do the same thing!

Check the injector wiring and common battery +12 volt supply. If there is a resistive connection in the 12 volt supply then the injectors won't fire, or may fire intermittently. The DME grounds the other side of each injector connector to open the injector.

All of the injectors fire together, if one of them has an intermittent short, the DME will shut down the injector pulse. Try disconnecting each injector one at a time and then starting the engine to see if that affects your problem.

Also, check and clean the smaller wires at the battery on the positive and negative post clamps. Not unusual for corrosion to form and cause problems. Check the condition of the small ground wire coming off the negative terminal to the chassis ground also.

[wwells7]

Thank you for your help! I'll check all that tomorrow. Have a great evening!