motor runs on ether. when key on, the pcm turns on and has shows engine light. when cranking it shows 55 on the engine light flashes. my nexiq will not communicate with this ecm to see if it has any injector codes fuel pressure is 20 during cranking, i restricted the return hose to raise presure to around 50 and it still will not start any suggestions before we send the computer out? tachometer works on instrument cluster so i believe the engine can see the timing sensor.
What’s the serial number? The tach might be running off a flywheel speed sensor so it could still be a timing sensor. Try pulling the timing sensor to clean and adjust the clearance. Check the fuses and power supply to the ecm. There should be 3 positive supply wires and a key switch power but we need a serial number to confirm. There might be a fuse in the battery box area if it’s a truck.
Thanks for the reply, it is a 7lg09204 It's in a 1994 l9000 ford tandem tractor. The fuse above battery going to pcm checks good, I'll check the timing sensor. Do you have a connector pinout so I can validate the proper pins have power please?
40 pin or 70 pin ECM? Being 94 I’d guess 40. Lotsa pin outs on the interwebs for that. Based on previous experience and tail chasing here’s where I’d start. Find the pin out so you know which pins are power and ground. 70 pin have several grounds. Get a headlight bulb and make a test light that will draw a few amps. Check your powers and grounds that way. I’ve had them ground just enough that the computer would hookup and read codes etc but truck wouldn’t run. The lack of communication makes me wonder if you have a power or ground issue to ECM. Pete likes to put a plug for the main power and ground about 2’ from ECM and it likes to get corroded.
It's pre 40 pin
To the OP. Check your messages.
And you'd be right...... Batt+ on Pins #1 & 11 Batt- on Pins 12 & 21.
Pulled timing sensor out and cleaned it Truck runs fine now Thanks much everyone