Cold driving issues

[smokinstroker92]

My buddys service truck is having some problems running while it is cold. When you first crank it up after it has been sitting for a period of time it will crank fine but as sion as you try to drive away and give it some throttle it dies hard and sometimes will cut off. If you let it sit an idle for a period it will run fine most of the time.
The truck has a new fuel pump, new hpop, new ipr, new icp sensor, new fuel tank, and 2 new injectors. Let's just say the guy he had work on it just threw parts at it.
After checking it over I watch the icp when I started the truck and while it was having the issue. Once you start to go it builds pressure like normal then it will fall off bad and start running rough and sometimes cut off. When you try to restart it, it takes at least 10 sec to try to fire then it isles real rough for a few minutes. Upon restart the icp will spike way up I saw as much as 3400 psi at one point. I pulled the plug on the hpop resevior and it began pouring out the hole and looked pretty aerated. I'm thinking that something is causing the oil to become aerated when its fed into the resevior and causing the problems. Where could the oil become aerated? What else could be the problem?

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[Lethalthreat7.3]

Sounds like you may have some debris or a restriction in the IPR. You can build pressure but not flow, kinda think like a kinked hose. Is it possible that an o-ring got stuck in there?

 

[smokinstroker92]

I haven't checked any of that yet but once warm the truck runs fine and it idles like normal around 550 psi and normal duty cycle. Seems like if had a restriction it would act weird all the time not just when it was cold.

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[ghohouston]

I wonder if the "mechanic" took time when he dropped the tank to clean the fuel sending unit's filter socks. I have seen them absolutely clogged, its always a possibility, especially since its a service truck and probably fills up in some rough climates?

 

[smokinstroker92]

I would think so, he supposedly put a new "liner" in the tank itself. The mechanic is one of the most respectable mechanics around this area but mostly works on big trucks. The fuel seems fine the fuel bowl will refill in a few seconds with ease seems to be no restriction there.

Any other ideas??

 

[ghohouston]

Well these trucks will idle fine with very little fuel pressure, its once you get going/ under a load, when there is either not enough pressure or the fuel literally cant deliver at the rate needed, I.e. clogged screens, bad fuel pump, I know you said it was replaced, but could still be bad out of box, I would check fuel pressure at idle and while under a load or driving

 

[smokinstroker92]

I will check it as soon as I get a chance. The only thing that gets me about that is that it will only do it when cold once its warm or you have let it idle for a period it usually runs fine with no issues what so ever. Thanks for the help

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[2000wa250]

Back to basics...what oil are you running? What tunes? Where did you get the injectors? How long ago was the work done?

Sounds to me like either your oil needs to be changed, you have an injector bleeding pressure when cold (2 new injectors that could be out of spec depending on where they came from), or you still have air in the system.



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[smokinstroker92]

It's has new rotella oil in it. The injectors are new alliant injectors. And the truck is bone stock no chip no exhaust nothing. This is not a problem that just occurred after the work was done to it the shop that did the work was trying to fix the cold driving problem.

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[smokinstroker92]

Anybody have any ideas

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[smokinstroker92]

Nobody has any insight on this problem?

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[Bobs 7.3]

How many miles were put on the truck since it was fixed? It could take up to 300 miles of interstate driving to work all the air out of the system.

 

[smokinstroker92]

It may still have a little air in the system but will crank fine cold just acts up when its cold. Once warm it does not act up any

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[golfer]

Anybody have any ideas

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http://swampsdiesel.com/files/7.3LInjectorDiagnostic.pdf

 

[smokinstroker92]

Thank you that was very helpful. The only thing that puzzles me is that when the truck begins to run rough the icp is falling was off becoming very low. The truck starts great no matter if its hot or cold. It will start up and idle fine. Just when you try to drive it when still cold after sitting over night it will idle very eratic and try to cut off. While this is happening the icp is falling off and dropping way down. Once fully warm all issues seem to go away, it idles great and runs great.