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Discussion Starter · #1 ·
Ok, I have a 97 F-250 with the 7.3 engine that I had to replace the engine about a year ago after catastrophic failure at the repair shop.
The original engine had a no start problem due to the oil pressure being to low even after a new HPOP. When I was unable to figure out the problem myself I took it to a local shop that in trying to diagnose it pressurized the oil system with oxygen and blew the left head clean through the hood as well as started the engine on a small fire.
After getting the truck back from insurance I bought a used motor from an automatic truck (Supposedly the same year though Engine sticker says 96) and installed it. After installation I ran in to the previous low oil pressure no start again.
Here is what I know:
1. HPOP will produce 4000+ PSI at the right head with a stuck closed IPR.
2. Truck will start with stuck IPR but not a new one (Have 1 new, 2 rebuilt IPR's now)
3. 22 fuse is not blown.
4. Have solid current from IPR back to computer when putting power through the wires.
5. Changing computer mounted to fender as well as computer mounted just into truck cab makes no difference. (Have multiples of both computers)
6. Changing Crankshaft Sensor makes no difference.
7. Oil cooler seals leak when motor starts with stuck IPR at 4000+ PSI.
8. With New and Rebuilt IPR's truck will only get up to 300 PSI at right (Passenger side) head.
9. Used Engine supposedly ran fine before I got it.


Replaced Parts:
IPR (1 NEW 2 REBUILT)
Crank shaft position Sensor
Engine (USED)
Engine wiring harness (USED)
Fender computer (3 USED)
Computer just in cab bellow fender computer (2 USED)
Many other parts replaced though not connected to the No Start issue.


At this point I have no idea what else to check, diagnose or repair. If anyone has any idea's where to go from here that would be a HUGE help. Thank you in advance!
 

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Is the Check Engine Light on throughout the no start? If it is, you should get them read and cleared and read again if necessary. Are the HP Oil pressures from a mechanical gauge or from ICP readings? That's quite a list of parts replaced which can make it difficult to diagnose, especially when harnesses and PCMs are replaced. What was the PCM "code" of your original 97 PCM (the computer on the driver's side firewall? Did you get the same number? What is the new one? The computer on the fender below the hood hinge is the Injector Driver Module (IDM). Cheers!
 

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Discussion Starter · #3 ·
At the moment I only see the Check engine light after cranking the engine (Not during cranking or when ignition is turned to on). The oil pressure is currently being checked by a mechanical pressure gauge. At the moment I am unsure of the code for my PCM though I can check it if it is possible to do so without a diagnostics hook-up? I might also add that t engine, PCM and IDM that are currently installed are supposedly from the donor truck. Another part I might add is that I found a bare silver wire wrapped around the wiring from my right rear injector harness connection on back at least 6 inches that look to have been cut at one time on the end. Is this just to keep the wire wrapped together? I also noticed that after a few attempts to start the truck the connection seemed warm (Maybe just from attempting to start the truck but I am unsure.) Thank You!
 

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The PCM code usually can be read with a mirror and flashlight right near the connector when its installed in the truck (it will be in a format something like NAW4, MIF7, JKA2, etc). If the bare wire is the one that wraps around the injector/glowplug wiring, that is to get rid of electromagnetic interference. What does the HP oil pressure do with the ICP disconnected? Cheers!
 

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Discussion Starter · #5 ·
When the ICP is disconnected (Sensor in the left head if I am correct) I notice no noticeable difference in the oil pressure. I will attempt to get the code off of the PCM installed in the truck tomorrow as well as the codes for the other two PCM's not installed.
 

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Apologies for the thread hijack. I keep getting the message that my post needs to be more than 5 characters.I'm also having trouble with my 97. My 97 powerstroke failed me last December and I've been trying off and on to run ever since. If the temp is below freezing it will start right up. After it's warmed up it doesn't start again until it's cooled off. Since warm weather hit it hasn't started without aid. I have replaced the HPOP, valve cover gaskets and related plugs, checked fuel pressure, checked injector high oil pressure, changed the IDM, and the fuel filter. The batteries and starter are new. No smoke when cranking. Once I start it with either it will run and drive until I shut it off then immediately no start. The fuel pressure is 57 lbs cranking and the high oil pressure will continue up to 2400 lbs cranking. It drops back to 500 at idle. I'm out of ideas so any help is appreciated. I'm looking for the really off the wall stuff that has hardly been heard of. If it's anything that you would normally look at, it's been done. I thought I'd try to see if anybody had anything here before I pull the engine and ditch the truck.
 
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