Noise at back of engine after HPFP replacement.

lmorris · May 2, 2012

Replaced a HPFP for P0088 yesterday. Roadtested and had no issues. Service manager drove it later on as it went into regen and I didn't have time to drive it for the customer. Customer picks it up later in the day and comes back stating there is a noise. Crawl under the truck and sure enough there is a rotating, scraping, rattling noise at 1500 RPM. Anyone else have to replace a new HPFP for being noisy?

BLittle500 · May 2, 2012

I had a metal "screeching" sound only at certain RPM, was a broken flex pipe on the left up pipe. It was a VERY loud noise too, maybe what your describing?

lmorris · May 3, 2012

I think it may be body related, as soon as I lifted it on the frame it went away. Then I have to drive it again for the noise to come back. I tried re-torquing the body mounts with it sitting on the floor but that didn't help. It is a definite vibration, I can feel it in the floor boards. I wonder if lifting the cab may have structurally changed it in some way.

Edit: Nothing is contacting the cab. This is very annoying. I am going to loosen all the mounts slightly and drive it again. Will update my progress.

Any other suggetions on body issues are welcome.

Steve Mutter · May 3, 2012

Does this truck have a bigger down pipe? Maybe it's hitting something on the back off the cab. Check to see if that engine lift bracket is on the back of the right head. Just thinking out loud

lmorris · May 3, 2012

Fixed. after removing the lower portions of each mount I noticed that the front 2 body mount bolt were not centered in the hole and were contacting the body. Repositioning the body fixed it.

Mekanik · May 25, 2012

Fixed. after removing the lower portions of each mount I noticed that the front 2 body mount bolt were not centered in the hole and were contacting the body. Repositioning the body fixed it.

That's good to know!