Dad changed the oil in his truck (05 6.0) and backed it out of the shop and parked it. Next morning-no start. Not building more than 200psi HPO, ipr full closed (84%). So I pulled the filter since i don't believe in coincidences, and the filter bypass was broken. the top part and the spring was there, but The bottom of it (2 small plastic ears) broke off and appears to have gone down into the HPO reserve tank, and I am sure is causing a blockage. I am guessing the screen under the oil cooler is torn, because it never had the cooler replaced, and the plastic made its way back toward the HPOP. My question is, is there a chance its stuck in the passage between the oil reservoir and the HPOP? Or could it actually be in the HPOP, keeping it from pumping? Its making about 200psi.

 

Maybe the oil reservoir screen (under the oil cooler) caught it.

Time to dive in and see.

You don't want pieces in your injectors.

 

I am assuming the screen is broken, and the piece (or pieces) got past it, and is either in the passage to the HPOP, or in the HPOP it's self. Would the HPOP chew up small plastic parts? Since I have a no start I am guessing its blocking flow to the pump, or got into the pump itself

 

I doubt that plastic parts will block much flow unless it is because they are "partially" blinding off the reservoir (HPOP suction) screen. The HPOP is quite "powerful" and some big plastic in the piping inlet might get stuck, but if it is small enough to even enter the pipe, I would bet it made it to (and through) the HPOP. The HPOP will chew up plastic parts. Some will get stuck on the IPR screen. Some (or even most) can go through the IPR screen, cause it to stick open (which could be why you have low pressure), and even plug injectors as mentioned earlier.

 

Its 2 plastic pieces, about the size of a #2 pencil eraser, so I doubt that is enough to block the screen. So if it got past the screen, (if the screen is torn) maybe it got chewed by the pump and got into the IPR... I'll pull it tomorrow and see. might pull the turbo feed too to see what kind of flow is there when cranking....

 

Pulled the IPR, looks fine. Plunger moves freely with about 1/8" of play. Has me baffled, I guess air test it or pull the oil cooler and have a look

 

You're actually talking about the anti drain back valve, I think?

With that missing would this not cause a no start?

 

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No, talking about the bypass valve in the top of the standpipe.

The bottom of it has ears that attach to a spring, both of those ears are broken. (both about the size of a pencil eraser)

 

Ok guys, did an air test straight from the IPR and I had air blowing straight back through the filter housing. I rotated the engine one revolution and the airflow stopped (although I could hear "bubbling" back by the HPOP). Rotated it another revolution, and the airflow started again back through the filter housing. I'm guessing I have something going on in the HPOP? Maybe a piece of plastic got into the wrong part and messed it up?

 

[/QUOTE] Did you ever find out what was causing your issue?