Engine/Transmission (1998.5 - 2002) Declining boost, Serious?

[groser]

Stock engine with 72,000 miles. Used to get 19. 5 boost, now get 18 psi. I think TDR Issue 47 (which I seem to have misplaced) said normal boost was 20 PSI@ 330 RPM.

I'm not sure when boost started declining because I can only check it when towing. I've suspected low lift pump pressure, installed warning lite (5 psi) and it came on frequently for 30-60 seconds whenever I hit the throttle. Installed a FASS fuel system, lite stays out now. Can a weak injector pump cause low boost? If so, I'm afraid I didn't catch the bad lift pump in time. Truck does not stumble, smoke and EGT seems about same but it's hard to tell. Pulling power seems normal. How do check for max power when not towing or on dyno? Is there simple check to tell if injector pump output is weak? Am I worrying about nothing since truck seems to run ok although in the recent hot spell I am having a little more difficulity with engine temps in Colorado on their longer, steeper grades but then I never tried long pulls at 100 degrees ambient before. Any help appreciated, my diesel knowledge is weak.





Yr 2001, 3500, SLT+, Auto transmission, 4. 10 rear end, ATS 5 star TC with valve body, ATS Co-pilot, PacBrake, ATS transmission pan, FASS fuel system , A-Pillar gages, KN filter, towing 34 ft 5th wheel between Denver, Lake of Ozarks and Alaska and points betwix

 

[Eric Lee]

One of my favorite mods, one that had the most obvious positive results, was a set of PDR intercooler boots and clamps. I know the stock ones might look like they hold air... ... ... . I had a hard time holding a boost at constant speed or using the cruise until I installed those. Personaly I don't think the originals (OEM) can be trusted. -Eric

 

[Dave Ratcliffe]

I agree with giving the intercooler boots a check. The boot just off my turbo actually wore through from rubbing when shutting down the engine. It was about a 1/2" tear in the boot that caused me to lose 5+psi. I had noticed my turbo made a lot of noise when I drove past concrete barriers, etc. but it wasn't until a fellow TDR member told me that sound was air being forced out of the system (aka, a torn boot).

 

[groser]

THank you

Thanks for replies. Found a leaking passenger side boot. Ordered new BD boots but haven't installed yet.

This TDR is great. Between the replies and my research on this forum I learned where to look for leaks, how to make a plywood plug to check for leaks and how to correct the fender well rub problem that caused the tear in the boot.