1986 944 non-turbo injectors not firing

[Orca]

I have a 1986 944 non-turbo which pumps fuel to the fuel rail but does not fire injectors. I have replaced the injectors and tested the connections with a noid light, all came out fine. I am a bit stumped on what to check to get these injectors firing.

[944 Ecology]

Troubleshooting - Engine

[TibetanT]

Hello there:

Be sure your battery is charged and showing at least 12.5 volts. (Simple test w/o volt meter...turn lights on, start the car. If lights go dim...battery is bad.


Next, the usual suspects are as follows:

DME relay
DME/ECU brain
Reference and Speed sensors

Follow the troubleshooting process George has suggested above.
Keep us in the loop, so we can help.

Good luck.

[guru944]

Orca:

Check Your Harness Injector Grounds. ECU Injector outputs are "Open Collector". If your Grounds are weak or floating, you will have weak current flow and no enough to drive Injector impedance(s). This is a very bad problem on all the German cars(BMW Porsche/ VW/Audi, Mercedes Benz, Etc.).
If you can run a 8 Gauge wire from the Harness ground point located near your Flywheel sensor back to your (-) battery terminal. This usually works...(15 Min. Fix)
***Suspect Floating Ground***
Keep us posted.....Later.