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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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1 - 5 of 27 Posts
have you disabled the glow plugs and tried to start it up on ether??? ps little shot goes a long way!! sometimes the pick up tube will crack drawing air in system and will cause to not start but will run once primed. if it does start and run after prime recheck ipr and wiring then if still no problems found jack ass end of truck up about a foot and add 3 extra quarts of oil and see how it goes if all ok then its cracked pick up tube.
will it fire off of alternate fuel source and continue to run???
if your seeing 200# on scanner for hpop pressure at icp then you indead do have oil pump pressure just not the needed 500# to fire the injectors if you give it a small prime it should fire then if you hold throttle it should continue if it stalls at idle when let off afterwards bumm ipr VERY common. I do understand you say you have rebuilt or replaced. wiring can be bad you can do this to verify startup and ability to build 2400#
have you verified that you dont have a cracked pickup tube?? air being drawn causing oil to foam.
the foaming of oil can cause the ipr valve to not function as its designed causing poor or no running. oil quality and quantity is very important to these engines.
1 - 5 of 27 Posts
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