04.5 Ran rough for 2 days, won't stay running now

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getblown5.9

Ceritified Kleenex Dealer
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My father's 04.5 started running rough when he fired it up in the morning 2 days last week. He said it idled rough for a little bit then got warmed up and ran fine all day both days. I stopped by Friday after work and he fired up for me to hear, and it was definitely missing and won't idle for more than 3-4 seconds before shutting off. It starts almost instantly but idles rough then shuts down.

170k miles on it, it had 3 injector bodies replaced under warranty before 100k.

Seems the oil level might be slightly elevated, but doesn't smell like fuel. We have been there before where the oil was so high it was pushing out the breather tube badly due to the previous failed injectors.

No CEL at this time.

Does the rough idle and shutting off sound like an injector problem, or could there be something else at fault?
 
I lean towards injectors. I hate when dealerships only change the bad injector! But check the injector harness it usually throws a code but...
Also running a motor with diesel in the oil is a fast way to engine failure!
 
Does he have a fuel pressure gauge? I wonder if the CP3 might be getting weak and not allowing it to make enough pressure to continue running after firing.

I would lean towards injectors, but it might be worth looking at FP just to make sure the CP3 is getting fuel and then see if it is giving fuel pressure.
 
I am dropping a spare set of injectors off tomorrow for testing and balancing, then we will swap those into his truck. I am leaning towards the injectors because of the oil level.

Has anyone seen injectors cracked/leaking so bad that it can not maintain rail pressure causing it to stall? In my head this seems logical, but maybe that's not a possible reason here. He drove the truck 2 full days and said it only idled a little rough at the first cold start. After that I stop by to listen to it and at that time it won't even run, so whatever failed happened quickly.
 
Take a drop of oil from the dipstick and drip it on a napkin. The fuel will spread faster than the oil. but take that with a grain of salt. There could be fuel in the oil but not enough to show up like that.
 
getblown5.9 said:
I am dropping a spare set of injectors off tomorrow for testing and balancing, then we will swap those into his truck. I am leaning towards the injectors because of the oil level.

Has anyone seen injectors cracked/leaking so bad that it can not maintain rail pressure causing it to stall? In my head this seems logical, but maybe that's not a possible reason here. He drove the truck 2 full days and said it only idled a little rough at the first cold start. After that I stop by to listen to it and at that time it won't even run, so whatever failed happened quickly.
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Be sure you scope the cylinders!! This is how pistons are melted! Wish you had a rail pressure gauge!
 
I believe some scan tools will read out rail pressure, that would help with diagnostics a lot. The more common issues are faulty injectors, FCA, or rail pressure sensor. Leaking connector tubes can give errors but usually it after they have been moved. Cracks still happen.
 
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