I've been trying to diagnose what appears to be a classic HPO leak and doing a lot of searching on the forum. Hopefully someone can help me narrow down my diagnosis! Using Auto Ingenuity. Thanks for looking!

2003 F250 6.0L, 90k, no mods. Starts cold but won't rev much more than 1200 rpm or so. Became this way slowly losing power over about a 15 mile drive and needed to be towed home. ICP actual when cold is around 700psi, warm around 500psi. No start/hard start when warm. Desired goes up with the accelerator pedal but actual falls off down to 400psi and goes back to an idle. FICM voltage hovers between 46.5 and 47.5 volts when running and warm. IPR is about 35% when cold idling and then goes to 85% when warmed up. Low pressure oil cranking is good. Here's what I've done:

ICP sensor was leaking, replaced that and the connector.
Removed the IPR, screen looks good and clean.
Pressure test with shop air through the ICP port. I can hear slight leaking/gurgling from both valve covers (listening with a tube, IPR at 100%). Only previous work beyond usual maintenance in the last couple years has been 4 injectors replaced.

My next step was going to be valve cover removal to listen more closely to the leaks but if it's the HPOP I'd rather not waste my time and just dig into that... any thing else I should check?

Thanks for the help!

 

This is indicative of a pump on an 03. You would need to dead head test to varify.

 

Thanks Cheezit, I don't have the tools to do the dead head test but I think I'm willing to take a gamble that it's the HPOP. I'm hoping the fact that I can't hear any major leaks from one valve cover or the other points to it. From other forum posts, it looks like replacing the HPOP and checking the screens is really all I'll need to do if going that direction, if there is anything else I should do/replace while in there the advice is appreciated.

 

There is a tube that sit on top of and bolts to the pump. It supplies the branch tube. They get worn and leak at the stc.

 

Ok, I'll add that to my list! Thanks again for the help, I'll let you know how it goes...

 

Correct me if I'm wrong but if it is leaking from valve covers then yr Leak is under valve covers: stand pipes, d-plugs, nipple cups on rail or injector seals... if it was pump it would leak from near the pump.. do you have anything to monitor yr paramaters?

 

Ok your correction...
An 03 6.0 is much more like a 7.3 system and does not have alll the same parts as a later 6.0.
Also note an early truck runs a swash plate and not a piston pump

 

My assumption was that since I can hear the same air leaking sound on both sides, what I was hearing was actually from the HPOP.

 

That would be correct asuming the ipr is commanded shut.