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1996 Ford F-250 7.3 4x4 Supercab
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72 Posts
Discussion Starter · #1 ·
New user here, thanks in advance for any help/guidance...
I bought my 96 f250 7.3 a couple months ago. It was hard starting when I got it. I bought an ob2 mx scanner and ran a buzz test using forscanLite. Injector #4 was bad. Also had some bad connections on the valve cover gasket harness. I replaced the bad injector, a few bad glow plugs (tested them all), replaced the valve cover gasket harness and new pigtails. I had a bad cps and replaced that. After that work I cleared the cylinders of oil and fired her up. She ran very strong and steady for about 30 minutes in the driveway before I started down the road only to break down after 2 miles. After several attempts to get started again, I towed it back home to look deeper. During this evaluation, my electric fuel pump died. I replaced that along with the single blown fuse attached to the positive cable from the pump to the battery. After that she fired up immediately and drove extremely well all night for about 75 miles. Parked her...went out 7 hours later in the am to start back up and nothing but crank no start ever since. Have not been able to get her started back up after that nice drive. I do get RPM movement on the tach.. I have not plugged in my block heater (it doesn't work and needs to be replaced), but it has been in the 80s and 90s where I am so I feel like that isn't a culprit. I have a feeling that I am narrowing it down to some electrical issue even though I've checked all fuses and relays and have inspected the harness thoroughly for any corrosion or compromises. And so if not wiring, possibly bad ipr/icp/idm? By the way, I am not getting any diagnostic codes out of my obd2 mx using ForscanLite
 

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Registered
1996 Ford F-250 7.3 4x4 Supercab
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72 Posts
Discussion Starter · #3 ·
Yes, all assumptions are correct.
Tach does move while cranking, not a lot at all, but it moves.
Irate diesel electric fuel system - regulator reading about 65-70 psi.
Oil clean and topped off. Popped hex bolt off of hpop and I see oil right below the hole.
I have not tried checking the ICP/IPR % thru forscan, didn't know that was possible...I am new to diesels, new to 7.3, new to scanners and forscan. I've just been diving deep researching and doing my own work.
What test specifically on forscan to test these levels? Thanks a lot Patrick
 

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1996 Ford F-250 7.3 4x4 Supercab
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72 Posts
Discussion Starter · #4 ·
775713
775714
775715
775716


Tried to post a screen record of forscan while I was cranking but it wouldn't support mp4. So I posted a few screenshots if what the test was showing while I was cranking. Trying to find information now on what the levels should be reading.
 

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1996 Ford F-250 7.3 4x4 Supercab
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72 Posts
Discussion Starter · #6 ·
The last one is showing the IPR at maximum commanded duty cycle, while the ICP pressure is low. ICP needs to be about 500 for the PCM to command the injectors to inject fuel. You might have a leak in the high pressure oil system somewhere. I've attached a good reference for you. Cheers!
Awesome thanks a lot Patrick, I appreciate the guide.
 

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Registered
1996 Ford F-250 7.3 4x4 Supercab
Joined
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72 Posts
Discussion Starter · #7 ·
The last one is showing the IPR at maximum commanded duty cycle, while the ICP pressure is low. ICP needs to be about 500 for the PCM to command the injectors to inject fuel. You might have a leak in the high pressure oil system somewhere. I've attached a good reference for you. Cheers!
Wait I can't open that rar file...can you please upload a different format, maybe pdf if possible?
 

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1996 Ford F-250 7.3 4x4 Supercab
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72 Posts
Discussion Starter · #9 ·
It isn't in a RAR file format(???) It is a PDF. Cheers!
Cool doc, thanks. Yeah I don't know why when I just click the attachment/link it takes me to a rar file opener. I had to copy the link and email it to myself in order to open it. Got it now though, thanks Patrick. View attachment 775727
 

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