Black smoke

[20THOR]

My truck has a new found power and willingness to move lately not that I'm complaining at all, but anything over roughly 1/3 throttle and I get black smoke from the exhaust and a mad rush of acceleration, truck is 100% stock, according to the SGII FICM main power fluctuates between 47-48v, everything seems fine except the black smoke. not sure if to not worry about it or dig deeper to see if anything is wrong. engine is running smoother than it ever has doesn't stumble, run rough. it is early 2004
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[Enterko]

Make sure that your turbo VGT vanes are operating freely. You could be experiencing some vane cycle issues causing them to be stuck either open or closed.

[20THOR]

watching the boost on my SGII it moves quickly, i can't hold throttle down long enough to see max boost(roads and cops around here suck) but it does build pressure quickly and seems to be responsive

[howell_jd]

In addition, check the boots from the turbo to the hot side CAC tube, the hot side CAC tube to the intercooler, the intercooler to the cold side CAC tube, and the cold side CAC tube to the intake elbow. These boots may develop cracks and the lost boosted air pressure will result in insufficient air to fully combust the added fuel resulting in black smoke.

Ultimately though this sounds like sticking VGT vanes.

Jonathan

[Enterko]

Originally Posted by 20THOR

watching the boost on my SGII it moves quickly, i can't hold throttle down long enough to see max boost(roads and cops around here suck) but it does build pressure quickly and seems to be responsive

Does it smoke from a dead stop or when you roll into it?

[20THOR]

roll in to it

[Enterko]

Is it tuned at all?

[20THOR]

not that I'm aware of and i'm 99%sure the previous owner didn't either, 100% stock i'm pretty sure

[Enterko]

Yeah you shouldn't be smoking at all then. Do you have a way to check VGT vane duty cycle?

[scmedic85943]

Could be bad injectors as well. Uncles 6.0 was doing same thing and it was his injectors. You could always take it to a master tech and they should be able to pull up tunes if your previous owner loaded them and forgot to tell you. The tech can also check pretty much everything with the engine and tell you what's up usually just by plugging the obd2 port. If he's with our times and not still using 1980s methods

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