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Discussion Starter · #1 ·
I have seen lots of information on no crank 7.3 but I have some questions.
95 7.3 with 48k miles, I'm original owner and truck was backed into garage, and then 2 months later, no crank.
I have isolated down to the HPOP. I have capped the HP oil lines one with JIC cap and the other with a gauge.
i have 200psi while cranking with good batteries.
my next step is to pull inspection cover off to check the HPOP gear bolt.
what is the likely hood of truck running, then parked, and the bolt coming loose?
its very odd to me this has happened this way. No warning, no rough running or hard start previous.
just wandering if anyone has any ideas?
It'll probably be a few days before i get another chance to piddle with it.
 

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I doubt you'll find the gear bolt loose. It can't loosen up by itself, especially if it hasn't been running.

Before you condemn the HPOP, put a new IPR on it. The only way to tell the difference between a bad HPOP and a bad IPR is to install a known good IPR and retest.

Before you do that, be sure the IPR is getting the right signal and reacting to it. If you put 12V continuously across the IPR coil, the HPOP should go to max pressure. But if the IPR isn't good, it won't even do that.
 

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Discussion Starter · #3 ·
It had a new IPR and checked 12v and ohmed out to 42 pin connector. Also ohm the coil from original and new coil are the same, between the 10.5 -11ohms.. Sorry I didn’t mention in original post. I’m new at this.
the only thing I haven’t done is jump full 12 to the ipr.
I will try 12v on next attempt.
 

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Discussion Starter · #4 ·
It had a new IPR and checked 12v and ohmed out to 42 pin connector. Also ohm the coil from original and new coil are the same, between the 10.5 -11ohms.. Sorry I didn’t mention in original post. I’m new at this.
the only thing I haven’t done is jump full 12 to the ipr.
I will try 12v on next attempt.
12V straight to IPR gives 3600psi. Now question is why is the IPR is not getting the signal it needs? see lots on OBDII trucks for diagnostic, but not much on OBDI.
will see what i can find and figure out.
 

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Hey, Strokin36 Welcome to the forum what is your truck doing when you are trying to start it?
 

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Discussion Starter · #6 ·
It just spins over. I have isolated down to the iprv is not getting the proper communication. I ohmed the pigtail to the 42 pin connector. Applying 12v straight to the iprv, yields 3600# on hpop. I have to reconnect heads and verify pressure on entire system with external 12v.
I will have to run down what the missing link to iprv is.
no drivability issues before. Just got in truck and no start.
my gut filling has been electrical issue from the beginning.
 

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Hi! Stroking36 I too just had a crank no start on Saturday got it fixed on Sunday. A little history on what mine did I drove mine about 1000 mi. 3 weeks ago no issues whatsoever a week later we had a forest fire that was threatening us so, I had my friend come and get my truck, trailer and bike and take it to his place no issues whatsoever. He parked it and 2 weeks later which was Saturday he goes to start it and bring it back to me it fired right up 45 secs later it shut down he tried again 5 more times and nothing it would just spin over really fast. So, he came and picked me up I took my volt meter and charger with me checked the batteries 12.4v had him turn key it dropped to 11v had him try to start it and it dropped to 10v. I was thinking it might be a bad battery but, I forgot my battery load tester so, we just put a charger on it over night I went back yesterday pulled the battery cables off and cleaned the cables and battery posts off load tested the batteries which tested good. I was bummed I was hoping it was a bad battery so, I hooked everything back up said what the hell and tried to start it and she fired right up and purred like a kitten drove it home with no issues. I was told years ago that a film builds up on the battery posts and cables and can mess with the electronics not sure if it is true or not but, that you should clean them once a year regardless after this I'm a believer in doing that. The last time I had cleaned the battery posts and cable ends was 14mths ago when I had to replace my engine.. As simple as it sounds clean the posts and cable ends and try to restart it you have nothing to lose but, a few minutes of time. Hopefully, your fix will be as simple as mine. Good luck! and keep us posted.
 

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Discussion Starter · #8 ·
Ok. Been a few days, but here’s what I have. 12v straight to iprv and get high pressure. Ohmed out ipr harness all the way to pcm connection. On the ipr pigtail KOEO you have voltage across it. When load from iprv coil is applied voltage drops to nothing.
i back-probed right at pcm connection and same thing, even using a jumper pigtail to bypass factory harness.
Every thing is pointing to faulty pcm. I’m not sure why it gives voltage until load is applied.
How common is it for the pcm to just up and die? Truck ran parked in garage then dead as a hammer.
 
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