I have found the PCM is not grounding the ignition coils for 4 of the 6 Cylinders. Cylinders #1 and #6 are the only ones being grounded by PCM. I have scoped the cam and crank sensors, swapped coils, checked all related wiring from PCM to coils and sensors and all have checked good. PCM ground and powers supplies checked gOod also. I had concluded it was a faulty PCM and had it sent off for repair. The Chrysle PCM repair shop said they found no internal damage and supposed it must have had a virus from what I told them. They tested it and updated the software. I installed it and found I still have the same problem. I'm at a loss for ideas now. An important note is that the vehicle had a used motor installed prior to the problem. The owner of the car said it ran bad after the motor install but he was able to drive it home and it hasn't ran since. The car will run on 2 cylinders but on if it is started cold. After it is shut off it won't start up and will only crank over. I have let it run on 2 cylinders for over 5 minutes straight and it won't set a CEL and have viewed the misfire monitor via my snap on verus and the monitor doesn't register any misfires thought its blatantly obvious. Please help me!
Have you tried checking pulse at PCM when installed?
March, 18, 2012 AT 12:41 AM
Yes. This is how I know that they are not being grounded by the PCM. All my signal checks have been made at the PCM to eliminate extra diag work.
March, 18, 2012 AT 7:31 AM
You tested with injectors connected? Have you tried with them disconnected?
March, 18, 2012 AT 12:11 PM
Yes all checks have been made with injectors connected. I have not tried with the injectors disconnected. The injectors and coils share the same power supply, but outside of that I dont see the difference in having them connected or not as far as the coils being grounded goes.
March, 20, 2012 AT 9:05 PM
Hook up a noid lite on the injector harness if its pulsing check injector solenoid if not further chck wiring back to the computer for short/open circuit also go back and retest the cam and crank sensors and its circuits. Let us know
March, 24, 2012 AT 8:21 PM
All 6 injectors are being pulsed by PCM. Cam and crank signals are good. I have checked and recheck these multiple times.
March, 24, 2012 AT 8:45 PM
What type of tests did you do on the CMH and CPS sensors?
March, 25, 2012 AT 12:25 PM
Used a lab scope and viewed both signals while the engine was running. They are both hall effect sensors. They are both being Pulled down to zero and are also reaching the proper 5volt amplitude.