6.5 tb- Turbo not spooling - Diesel Bombers



Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

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Old 04-17-2012, 10:27 PM
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Default 6.5 tb- Turbo not spooling

I have a 1995 Chevy tahoe with a 6.5 turbo diesel in it. When I try to spool the turbo to do a launch the turbo doesn't build up boost. Once I'm actually moving then it does build boost. Is that normal for it not to build up boost from a stand still? If its abnormal what are the fixes?
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Old 04-19-2012, 11:23 PM
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vaccum system or turbo master?
black smoke? need more info
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Old 04-21-2012, 08:54 PM
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Check wastegate system...
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Old 04-27-2012, 04:00 AM
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It has a makeshift turbo master. It's a little ghetto but it accomplishes the same thing as a turbo master. As for the smoke, it blows black smoke when driving but upon start up it puffs a little grey/white smoke. Is it normal for the turbo not to spool up from a stand still or should it be spooling?
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Old 04-27-2012, 09:37 AM
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its a small turbo its gonna have turbo lag, also did you put rear end gears into consideration? and is it black smoke when you punch just a little smoke or constant smoke
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Old 04-28-2012, 06:03 AM
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The GMx series turbos will build a couple psi with a TM and no load, but only for a second or two. Boost is dependent on fueling, thats what creates drive for the turbine.

Does it build boost when driving or is it flat?

If none while driving, you have a wastegate problem or something is wrong with the turbine, compressor or the shaft/ bearings.

Alternatively, it may also have a boost leak somewhere in the intake manifold.

Quote:
Originally Posted by ebarresi5894 View Post
its a small turbo its gonna have turbo lag....
Incorrect.

Smaller turbo = less "lag".

Bigger turbo = more "lag".

The GMx series turbos build boost instantly, no lag. They are sized and designed to work this way.

At least, no "lag" on one that is working correctly.

An electronic 6.5 that smokes black when driving indicates a lack of air supply for the fuel commanded. That means a turbo mechanical or control problem of some sort or perhaps a boost leak.

A really filthy air filter will also make it smoke a bit black from lack of air, but it would have to be almost clogged solid.

I would suggest you might have a problem with your wastegate or "homemade" TM....


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Last edited by great white; 04-28-2012 at 06:15 AM.
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Old 04-28-2012, 07:12 PM
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Yea sorry about that last post my mistake
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