Guys I need help!
Playing in the Dirt
Joined: Oct 2005
Posts: 2,302
Likes: 1
From: Southwest Georgia
Cody, sorry to hear about all of your hard work and then the end results, your a good man to try help the guy out. Also sorry that I have been out of pocket and did not see this thread sooner.
I had a truck like this that stumped me for a while, found out, through hours and hours of test and bugging every diesel guy I know, that it had two injectors with bad o-rings in one head. Truck would crank up and die after 10-15 minutes and then not crank back until sat for several hours. HPOP stayed full because everything was working (i.e. LPOL, HPOP, IPR, ICP, etc.)
To test it and find it, you isolate the High Pressure Oil system to one head (remove the feed line and cap it and cap/plug the head connector), crank the engine and if she fires and runs you found the head with the problem. If it will not run isolate the other head and try again. Once you find the head pull the valve covers and locate the bad injectors (oil coming from around the base) and replace the o-rings.
What was happening in this case is the HPOP builds pressure in the system, once the pressure is up above 500 psi (sensed by the ICP) the PCM singals the injectors to fire. It cranks and runs until the HPOP pressure drops (oil leaks past the o-rings) and then the PCM quits firing the injectors and the truck shuts down. It had to sit until the o-rings/oil cooled down until it would fire again. The longer we worked on it the less it ran until it would not fire at all.
You can also check the above by installing a high pressure gauge on the oil lines to the heads as you isolate them and you can watch the oil pressure drop off.
Maybe this will help next time you run across one like this.
I had a truck like this that stumped me for a while, found out, through hours and hours of test and bugging every diesel guy I know, that it had two injectors with bad o-rings in one head. Truck would crank up and die after 10-15 minutes and then not crank back until sat for several hours. HPOP stayed full because everything was working (i.e. LPOL, HPOP, IPR, ICP, etc.)
To test it and find it, you isolate the High Pressure Oil system to one head (remove the feed line and cap it and cap/plug the head connector), crank the engine and if she fires and runs you found the head with the problem. If it will not run isolate the other head and try again. Once you find the head pull the valve covers and locate the bad injectors (oil coming from around the base) and replace the o-rings.
What was happening in this case is the HPOP builds pressure in the system, once the pressure is up above 500 psi (sensed by the ICP) the PCM singals the injectors to fire. It cranks and runs until the HPOP pressure drops (oil leaks past the o-rings) and then the PCM quits firing the injectors and the truck shuts down. It had to sit until the o-rings/oil cooled down until it would fire again. The longer we worked on it the less it ran until it would not fire at all.
You can also check the above by installing a high pressure gauge on the oil lines to the heads as you isolate them and you can watch the oil pressure drop off.
Maybe this will help next time you run across one like this.
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