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7.3L starts but dies when operating temp is reached

17K views 5 replies 6 participants last post by  RT 
#1 ·
have a 2000 F250 with a 7.3, AT and 4x4. Here's what's going on and I appreciate some help.

I realize this is a used truck and it has about 190k miles on it. A few weeks ago it just died and I replaced the cam sensor. Truck started and ran a week just fine til one day it just quit again. So towed it to a referred diesel mechanic here in NE Texas and this is what all that has been done.

New High pressure oil pump
2 new injectors, all others checked and good.
New injector o-rings
new injector wiring for under both valve covers and new gaskets
new icm and I think it's an edm that was replaced.

Spent a LOT of money when in the beginning we told them if it was going to be too much we'd just put a low mileage motor in it. Well after giving shop a cc they kept replacing and calling that it wasn't it.

So now they think it's something inside motor and want $4k to tear it apart to figure it out. Seems they have no idea at all.

The truck will start and run fine til it get's warmed up and it might run 3-4 minutes or 10. Then it dies. After sitting a bit, it will fire right up.

It will also start up and if you turn it off after a cpl minutes, it won't restart until it sits a bit.

Please help. Also, I am in NE Texas near Commerce it anyone knows a VERY GOOD Master Diesel Tech around here that actually diagnoses and then fixes the problem. We're to the point of just dumping the truck but if we can spend a reasonable amount and get this thing dependable we'd prefer that. It's had a cpl thousand worth of front end work and tranny is good, plus we need this truck running.

Thanks in advance for your time!!!

Davisix
 
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#2 ·
Sounds like either a failing cps, or an issue with the ipr. Either the ipr itself or the coil. If the cps was aftermarket go get a oem replacement

Also check to see if oil pressure falls off before it dies. Could be a serious hpo leak that gets worse as the oil heats up and thins out.
 
#3 ·
As Blue said, I would start by changing the CPS for another one. its a $40 that will rule this option out. IPR would be my second guess
 
#4 ·
I had the same issue two days ago while driving home from a vacation while pulling my trailer.After replacing the CPS to no avail, I stopped into a dealership where the tech nicely ran a code reader on it and it came up 1280 code. I replaced the icp sensor harness (I should have replaced it when I replaced the sensor) and the stalling issue went away.
 
#5 ·
So now they think it's something inside motor and want $4k to tear it apart to figure it out. Seems they have no idea at all.
Do NOT let them tear it apart. It's not something inside the engine. You're right. They have no idea at all.

When they replaced the HPOP, did they also replace the IPR (and the coil on it)? The coil can heat up and fail like you're experiencing. It cools off and makes contact again.
 
#6 ·
And one other possibility - there are several sensors on the vREF circuit that can short out and take down the whole line. The exhaust back pressure valve sensor is the most commonly identified culprit. It is very possible that the short is heat sensitive, so if a new CPS and a new IPR coil (still the most likely suspect) don't help, unplug the sensor and try to start it.
 
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