96 12 valve boost problem

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Diezeldriver

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Joined
Mar 1, 2009
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73
Truck runs fine to 10 psi boost then lays down runs real rough and puts out black smoke. Has 4000 rpm gov. spring, 60 cm/sq compressor in turbo. Fuel plate removed. 4" exhaust turbo back. Checked intercooler boots, not dumping boost there. This combo has made 40+ lb of boost, no changes made.
 
what does the boost do at that point does it drop to nothing or stay steady. I am thinking your turbo is going out and stops spinning once you get 10 psi boost or you could have a leak in your intercooler. Depending on what your boost does I would lean towards turbo.
 
As soon as it hits about 10 psi (you can get 15 if you hammer it) it falls off to 0. If you let off you can bring it back to 10 and hold it there all day as long as you don't try to get more boost.

Hey King, What did you do to that 96 to run 12's? Thats where we're headed.
 
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Sounds like a turbo problem to me. Pull the intercooler boot to see if there is oil in it. Maybe try to video it, right now Im confused why it would drop back to 0psi unless the turbo stops spinning??
 
I have seen farm tractors blow black smoke , like you are describing. It ended up being a crack in the intercooler.
 
after what you said I guarantee it is the turbo the bearing is shot take air cleaner off and look I bet there is nicks and marks on the compressor housing and wheel. If you listen close when you get over 10 and almost 15psi right when it drops to 0 I bet you can hear a squeal. And Pm me about my 96 I had.
 
Thats exactly what my motorhome was doing last summer !!

Took off the air filter and it was plugged full and squished flat from the vacume !
 
I didn't have a chance to run it and now the temps are in the low 20's. When it warms up I'll investigate the turbo and report back.

907 it still does the same with the air filter removed. Thanks for your input
 
Diezel, remember that day at holt during the bracket races when you guys went to launch and the truck sputtered... came back and the wheel wouldn't spin, took the turbo out and couldn't figure out why? Sound's like she's definately shot!!

I'll get with Mike and see his intentions on the truck and help him spec out a new charger for the truck.. in the mean time we've got a few stock HE351's (stock 04.5-07) that could probably be adapted to work laying around, or the charger in my truck will be available next summer and would be perfect after we have it overhauled
 
Krazeeun said:
Diezel, remember that day at holt during the bracket races when you guys went to launch and the truck sputtered... came back and the wheel wouldn't spin, took the turbo out and couldn't figure out why? Sound's like she's definately shot!!

I'll get with Mike and see his intentions on the truck and help him spec out a new charger for the truck.. in the mean time we've got a few stock HE351's (stock 04.5-07) that could probably be adapted to work laying around, or the charger in my truck will be available next summer and would be perfect after we have it overhauled
Click to expand...

OK, I think the bearings are gone, too cold to look at it right now!
I need 4 more posts so I can PM
 
KingS said:
after what you said I guarantee it is the turbo the bearing is shot take air cleaner off and look I bet there is nicks and marks on the compressor housing and wheel. If you listen close when you get over 10 and almost 15psi right when it drops to 0 I bet you can hear a squeal. And Pm me about my 96 I had.
Click to expand...

I'm working on my post count so I can PM you!
 
YOUNG GUNS15 said:
Sounds like a turbo problem to me. Pull the intercooler boot to see if there is oil in it. Maybe try to video it, right now Im confused why it would drop back to 0psi unless the turbo stops spinning??
Click to expand...

No oil in the boots and the're in good shape, will get after market boots soon.
New turbo on the horizon!
 
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