here is the deal... 99 f250 sd 6 speed 7.3 stock motor......i had a problem with the truck studdering, and no power so i changed the fuel filter and it ran okay for a day...acted up again, then i went with qwick's vw fuel pump mod...ran okay for a little bit....the truck has no power, and no turbo whistle, so i check the wastegate thinkin it was stuck and not allowing the turbo to spool up..... so then i thought maybe the cat was plugged because my truck was equipted with a catalitic converter, so i put on a full 4" stainless turbo back exhaust w/o cat and flow through muffler...same problem, no power wont get above 1900rpms... so i then remove the ebp sensor tube and clean it, doesnt do anything.... so just sitting there in neutral, i slowly rev the truck up at around 2100 rpms it sounds like its bouncing on a revlimiter, so i just pump it a few times and its blowing a lot of blue smoke.... i bring it to an idle and back up again a few times... on about the 3rd time there was a strange noise and when i let off the fuel the engine started to drop the r's and i heard the turbo whistle come in and wind down so i took it to the road and its running great.........does anyone have a clue as to what it can be??? im stumped.....i would just like to appologize for the extrememly long post and my spelling haha..and thanks to everyone on this site, everyone is very helpfull and i try to return the favor when i can....have a good weekend

 

my friends did something similar our buddy held it full throttle for 15seconds or so it was hitting the rev limiter also.he said the turbo was stuck it started working good again but he said the turbo is going out .

 

It sounds like your turbo bearing might be bad. If the engine is shut down while the turbo is still hot, the oil in the bearing cokes up and can eventually gunk up the bearing and cause excessive wear or even freeze up the bearing so that the compressor wheel doesn't turn. The blue smoke sounds like oil was leaking past the turbo bearing seal into the exhaust side. You need to pull the intake and inspect the compressor wheel and check it for side play and end play.

 

Do you think you could have gotten a bad batch of fuel that clogged your filter? With the exception of the blue smoke, it sounds like a fuel supply issue to me. Could possibly be a clogged pick-up tube in the fuel tank. Easy way to check that would be to drain the filter bowl, and see how long it takes for the pump to fill it back up. Shouldn't take more then a 3 or 4 seconds if I remember.

 

Did you ever check the exhaust back pressure valve while it was running poorly? Sounds to me like it was stuck closed.

 

dieselfuelonly-i thought it may have been bad fuel so i dropped the tank cleaned it blew the lines out, but a new pump on and a new filter..the pump is pumping more than a stock one so i think i can rule that one out

clux-i suspected the ebpv the whole time from the posts i read but i knew too little about how and what to check for...i unpluged the wires from the sensor and from the turbo pedistule and it ran the same...but then i cleaned the tube and everything out and it ran the same so i held it almost wide open for a bit and something happened now its running great

i have never shut my truck down hot i normally let it run for about 6 minutes which should be more than enough..i dont think that the turbo is goin bad because it is an intermitent problem and the turbo has no noise and seems sound, if the bearing were seized i think it should have some noise or something and wouldnt come and go, what do you think, i hope the turbo isnt failing.........thanks for the help and information

 

Since you're a 99 you've probably got enough miles that checking the turbo bearing for excessive play is probably a good idea. The shop manual says to pull the downpipe and use a dial indicator to measure end and side play, but that's a lot of trouble. When I suspected a problem with mine, we just pulled the rubber hose to the turbo inlet, and just used our fingers to check end and side play by grabbing the nut on the compressor wheel and trying to wiggle it in various directions. Unfortunately mine was so far gone that the compressor wheel flopped around like a rag doll, but the truck still made good power. If you do this also spin the compressor wheel with your finger to make sure it spins freely without sticking.

 

I agree with ernest. The blue smoke is definely oil andit makes sence that it would come down from the turbo. It won't necessarily have to make any noise to bad.

 

okay...thanks for the info i will check that as soon as i get some time

 

This would be my guess as well.

EDIT: Make sure the connecting rod has not come loose.....