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No start. How does ECM get oil pressure signal?

4222 Views 26 Replies 9 Participants Last post by  bukhntr
I'm working on a no start situation and I believe I may have lost lube oil pressure. Does the ECM require an oil pressure signal to start or will the engine start with no pressure until the HPOP reservoir is empty?

Does anyone know how the ECM gets the oil pressure signal? I know the sending unit on top of the HPOP supplies the dash guage with information but does it also signal the ECM that there is adequate oil pressure to start?

The HPOP is full. Engine has plenty of oil. I have changed the CPS and IPR and have tried disconnecting the ICP, but still no start.

I have checked for codes and have none except for low ICP signal when I disconnected it and a TPS signal which I always have since I spliced the wire for my idle throttle control.

Am I missing something here? /ubbthreads/images/graemlins/shrug.gif /ubbthreads/images/graemlins/confused.gif
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Did you check the whole harness going to the IPR when you replaced it? They are very prone to getting diesel in them and melting the insulation. That being said, you need about 40PSI at the FPR for fuel and 500PSI at the hose going into the head for the oil.

Are those pressures you gave me attainable just cranking with the starter?

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Yes thats what you need to start it. Actully the FP could be a little lower and still start but the OP has to be there before the PCM will fire the injectors.
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