HPOP FAILURE

[snw blue by you]

I just want to let those know who are interested, concerning a previous post[6.0L miss] that after untold hours of diag, hotline conversations, parts replacement, and a few days with a Navistar engineer, what was causing the miss was debris caught in the bank 1 oil rail check valve. This was an item that was replaced early on[both sides],but ended up getting recontaminated. after replacing the first time, the engine ran fine for about 20 min, then the miss returned, as a result tunnel vision ensued and all kinds of parts were replaced to no avail.

The Navistar rep was then sent, and I have nothing but praise for him! It is not that he did anything special, but he had a unique perspective of his engine that the Ford techs do not. After performing all the basics again, he was convinced that the issue lyed with the check valves[iCPV signal fuzzy, erratic switch rate, voltage good for pressures]. Now, he did ask me at least 5 times whether I had changed them, and initially this was annoying, but it was explained to me that most calls he goes on, he finds, things were not checked or done as instructed. Fair enough. I produced the originals and said I would be more than happy to remove the current set, which upon removal showed another piece of debris. A piece of metal approx .030"thick and about 3/16" in length.

A HPOP piston return spring!

I will save you the details of the repair, only to say the vehicle is repaired and the customer is happy. I will say however, I will no longer take for granted that a replaced or serviced part couldn't possibly be the cause of an issue.

Obviously the pump is the base problem in the story, and the check valve being held open at high RPM causing the miss, was the symptom.

I can only blame myself for not paying more attention as I went about my diagnosis, a mistake I will try and not repeat!

/forums/images/%%GRAEMLIN_URL%%/poke.gif

[Keith Browning]

Sounds like you spun yourself into an endless spiral of confusion. Been there myself and thank you for the reminder. You want to tell yourself that "it can't be" but just because it's new doesn't mean it's still working. Debris travels and it usually goes with the flow. You ALWAYS have to keep the bigger picture in mind and remember that components are part of a system and they can affect each other.

 

/forums/images/%%GRAEMLIN_URL%%/frown.gif I wish I could always remember that advice!

[Torqued_Up]

How about a noisy HPOP? Yep. Strangest freakin noise I have come across yet and hard to figure out. At least I didn't have to throw a lot of parts at this truck to figure it out. This pump was making a low pitched whining noise that was really loud and changed with th engine speed. I could make it change a little by commanding ICP up and down with WDS. Heres some advice for engine noise hunting if you use a stethoscope, take the tip off of the hose and stick the end up the back of the engine between the rear cover and the heat shield bolted to the pump cover. If the pump is bad the noise will be loudest there.

[Keith Browning]

Thanx Ed! But where the hell were you with this a week n a half ago? LOL! After jerkin around performing TSB's 05-21-9 & 05-19-12, swapping turbos and alternators I discovered that I had a noisey HPOP. /forums/images/%%GRAEMLIN_URL%%/banghead.gif Used your advice and looked for the noise from under the truck. /forums/images/%%GRAEMLIN_URL%%/thumbup.gif

 

Quote:

At least I didn't have to throw a lot of parts at this truck to figure it out.

Unfortunately I had to start throwing parts at it but at least I had another truck apart that could borrow parts from. I thought these pumps just failed? Never heard of them making noise!!! Live and learn.