C-15 Vibration/Air Compressor

Hi All I have seen a post on here about an air compressor being in question on a 2007 Peterbilt with a C-15. The owner said it sounded like someone was hitting the underside of his truck with a rubber hammer, and vibrating up the steering wheel and shift stick. I cannot find that post again to follow up and see if he ever found a cause. My 2007 is doing exactly the same thing, and have changed almost everything, and am now questioning the compressor or maybe the dampener again. Dampener only has 230,000mi on new original cat replacement.

Any advice is appreciated.
Thanks

 

2007 Peterbilt 379
When accelerating and now starting to feel it when deccellerating with jake pulling me down.
Can really feel vibe at 64mph when cruise pulls into hills.
Cab and engine mounts all new.
New injectors
New clutch, flywheel, reman trans
dampener has 230000 roughly
Thanks

 

Yes very much so in feet and also in my seat. When in a good pull the seat is one of the things that starts rattling now. Not so much when released and coasting. This happens most when into a pull. I just stopped and installed a fuel pressure gauge. I have it ziptied to my mirror.
68# at idle
76.5# at 1000rpm
81# at 1350rpm 64mph no load on.

I am going to try and watch when i get load on and see what we get.

Anyone know what a Cat c-15 MXS 625hp should run as for fuel pressures?

 

Thanks for the advice. I did find the old hammer story, and the guy said that he traded the truck.

Peterbilt tells me that my ride height and driveline is all ok. I have asked if we should try to do a balance on the drive system. They feel it is not needed, but have no other answer.

I am debating changing the fuel pump, but not sure if there is a special pump for high HP on a c15. It is a 625hp with a healthy tune. I feel that I am starving the injectors with only 68# at idle, 76# at 1000rpm and 82# at roughly 1350rpm. I have heard there are different pumps and different springs and i just want the truck to run the way it should. This is just frustrating the ---- outa me on this vibration, and I keep going through injectors.