96 7.3 lost power now no start

[Celboy24]

Ive read alot about this but have not solved my problem yet. truck was running ok and then lost power on hwy. pulled over and got restart on a few cylinders to limp home @ about 30 mph with severe hard shifts. Dont have a tool that will read codes but have no CEL on even when not running with key on. CEL light comes on right when key goes to run but drops out almost so quick as you cycle key. limited tools available but fuel pressure is over 70 psi while cranking at schrader valve, hpop is full, tach moves and oil guage shows normal after a few seconds of crank. checked all wire harnesses and repaired IPR connector as i found wires melted together at connector and about 6" into loom. Got one bank of cylinders firing after repairing IPR connector but no fire on driver side bank. moved truck off drive way on 4 cyl and now wont start again.

What am I missing? I keep going back to CEL not staying on before crank, is PCM failing?

[73rvhauler]

first off welcome to the org.i know for me last time my truck did this it was the uvch (Under Valve Cuver Harness). Mine sorted out and melted with no warning. Will your truck idle? if so start the truck and unplug each of the four plugs one at a time. when you unplug one that has no change and does not kill the motor you know what side you have to replace. Now the stealership will take you to the cleaner for this part like for 150.00+ if you have an international dealership in your area get the part from them it should only be like 50-75 from them. that is my guess to your problem i am sure someone else may have an idea of what it could be as well

[Celboy24]

Thx for the welcome and reply. had the valve covers off when diagnosing, all were good. first attemp was unplugging each VCH to see if it made a difference. so far i cant get more than attempt restart after getting it to idle on passenger half last time. when it did idle it was smooth with only passenger side firing but moving on 4 cyl was not fun. Im lost, first diesel truck and still trying to learn the differences from gas. my biggest problem is losing sleep when i cant make something run!

Thx for the ideas.

[madpogue]

The blink-of-an-eye CE light on RUN is normal. Kinda stooopid that the bulb check doesn't last longer, but there it is.

You mention left and right sides, but you have two connectors on each side, right? (Don't all OBS have four UVC connectors?) So you're getting nothing on either one on the left side? Have you checked wiring continuity on the injector circuits on that side? Not that it'd be directly related to the "stroke" (dead on one side) you're having, but did you check the glow plug functionality on that side?

[Celboy24]

checked all 4 harnesses, look good and continuity is good from conectors to injectors and glow plugs. no shorts from valve covers to IDM either? only thing im not able to see is HPOP pressure? IPR connector was repaired with an injector plug a friend had...if i have right term.. wires were melted back from connector about 6 in...fixed now which gave me start last time but dead again. still sounds like a couple cyl's want to fire but not enough to keep crank going around?....kinda like an old tractor

[madpogue]

Just a WAG, but maybe the high pressure oil is only getting to the one bank and not the other?

[Celboy24]

Yeah, not sure how it is plumbed, now I cNt get more than a stumbling attempt to start but no run...any way to check high pressure oil?

[Celboy24]

anyone know of a scanner that could diagnose while cranking since it doesnt run? I have a cheezy autozone reader for clearing codes when my techs mess up installing alarms but thats it. need to get truck back on driveway as the local cops are going parking ticket happy!

[sldghamr]

i have a 96er myself. there have been a couple times where i lost power. once cuz the fuel pump was dying. the other cuz the IDM was dying.

[Celboy24]

Wish I had a donor IDM, that was my first thought when i saw good fuel pressure. Just hate swapping parts till I find problem. My luck it's always the cheap fix last!