Wierd Boost problem

[bbudus]

I have a wierd boost problem. Here is the skinny...

Day 1 - No boost, turbo is not spooling at all, drives ok under normal acceleration, going up hill produces "the Cloud".
Day 2 - I live in Montana, going up a rather large, extended hill, egt up around 950, losts of smoke, getting ready to just back it down, then cough, and WHAM!! turbo kicks in and the truck just takes off.
Day 3 - Cannot get turbo to to pull any boost over 7lbs, cruising down the highway at 65-70 maybe 2-3lbs of boost.
Day 4 - Took it to a shop, turbo is fine, replaced turbo boost sensor, per tech 1 says it is pulling 18lbs, but boost gauge says 7lbs, lots of black smoke.

Truck has heath downpipe and crossover, afe cold air, and 3" exhaust all the way back to 18" glasspak, has heath chip.

I am absolutly stumped, shop thinks it is the injection pump, i disagree and am pleading for help before they pull pump and charge me for it.

Thanks,

Bryan

Ps. If you need more info I will be on all night

[Hubert]

Is wastegate linkages/mechanisms ok? Not binding or wobbling etc? Spring on TM still ok and like normal? Does turbo wheel turn freely and not hit housing etc?

Whats up again with that map/baro sensor and scanner reading 18 psi boost and guage only 7 psi ?????? Something is not right there should be same or very close.

[bbudus]

Yeah, turbo spun fine, wastegate was free, took the whole turbo master off. Everything seemed fine. Truck seems to run great just does not have enought boost, egt under normally running conditions are now 600f, they used to be around 450-500.

bbudus

[Mark Rinker]

Maybe your turbobearings are coked up and not spinning freely. (That happened to me back in the 80s alot.)

[bbudus]

Oh, and one other tidbit, pulls a code 78 a lot. I don't know if that will help but before i switched to the TM, my old system seemed like it was doing the same thing. No boost, black smoke, especially going up hills, and then the check engine light would come on, code 78.

Bbudus