Did you try starting it with the ICP unplugged? Any codes? Ficm voltage? Sync?

 

So now for the longer version. The ICP was replaced first and then the pigtail. I tried it with the ICP both plugged in and unplugged with no difference. I’ve replaced the IPR but not the pigtail for that. I’ve done continuity tests for both sensors and they pass that simple test. Originally the FICM was showing that it was working fine but through my attempts to get it started it lost sync and power. I do the power test at the Ficm and it shows between 48 and 52 V. We hook up the fancy computer and they are unable to fire the injectors. It appears the power side lost communication with the logic side of. So the ficm was sent off for testing. The only common denominator that I could come up with was the PCM so it was replaced but nothing changed. Now I’m left with the only common denominator being what I originally thought and the wiring somewhere having an issue. I’ve checked all the known chafing points and have found nothing. All of the contact points between the harness and the PCM looked to be fine. Thank you for taking the time to read into my issue.

 

I'm thinking the 300 may be actual. Have you air tested for leaks?

 

Air test done. The 300 was after 20 seconds of cranking. When hotwired the 700 was nearly instant. I did the upgraded dummy plugs and stand pipes while I was in there.

 

What are you getting when you crank it for 10-15 seconds? I'd pull the IPR and inspect/clean. Remember, IPR is a commanded signal with no feedback.

-jokester

 

I pulled the original and it looked fine. I replaced it, just thinking it was preventive maintenance. I’ve pulled it again throughout this endeavor and nothing appears wrong with it. The pressure starts out sub 100 when cranking and slowly builds to about 300 after about 20 seconds.

 

Does your oil pressure gauge move on the dash when you're cranking?

What is your battery voltage, RPM, ICPv KOEO and while cranking?

You said air test was done...i'm assuming you found nothing? Did you apply 12v to close the IPR when you were air testing?

-jokester

 

Yes, gauge moves, also pulled oil filter and it fills. Batteries are over 13v each attempt. Rpm’s are in range. Not sure what ipc volts are, but if unplugged, reading shoots up. I have not attempted air test while cranking, but when doing air test and applying 12 to Ipr air immediately stops going through oil pan or wherever it bleeds off and holds until 12v is removed.

 

Has the HPOP discharge (STC) fitting been replaced?

Ultimately it could be a bad HPOP if there is no leak, and if the IPR is operating as designed (this assumes that the 300 psig cranking ICP pressure is real, and it sounds like it is).

Sure would like to see a picture of your engine compartment, focusing in on the oil filter area.

Also, I assume your oil level is good (neither low nor too high)?

Did you hang on to the original PCM? It almost certainly was still good.

 

I did the stc when pulling stuff apart and it was fine, but updated it. Luckily, yes I kept the pcm, thinking the same. I’ll get pics out when I make it back.

 

After 3 months of what seemed like guessing, I went with my original thought and bought another Ipr valve. 10 seconds later, fired right up. This was also after a rebuilt Ficm. Apparently I fried the Ficm while trying to start it or hot wiring the Ipr. Stumbled a couple times getting the air out, but 30 minutes later, runs like it always had. I don’t recall where I got the replacement Ipr, but got the new one from xdp. Good reminder to use quality parts. Thank you all for the help. Let me know if you have any questions. I would love for this post to help someone else