Mechanics

SOMKES UNDER ACCELARATION 6.5 DIESEL

1996 GMC Sierra • 118,000 miles

This truck has a lot of black smoke comming from the exhaust when you rev it up or just going down the road. If you could give me some pointers on where to start diagnosing this that would be great.
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Rob.kela
May 13, 2012.



Most common issue is the injectors? How old are they and when did you have them serviced last?

If the injector timing is off, that will cause smoke as well.

Also, fuel quality is another factor. Old, bad low cetane fuel will do the same thing.

Roy

ASEMaster6371
May 13, 2012.
Changed a fuel solinoid driver also instaled a 8 or a 9 chip the stock was at a 7 does that effect it.

Tiny
Rob.kela
May 13, 2012.
The driver, no, the chip should not effect it. Is this a turbo? If it is, there is another reason it may smoke as the seals may be bad and oil may be going out the turbo into the exhaust.

Roy

ASEMaster6371
May 13, 2012.
Yes it has a turbo, is it posible the fuel lift pump is bad is there a easy way to check it, the injectors are original. The injector pump was changed at 80,000 after the fsd was changed it stiil never semed right. It is not consuming any oil it seames its getting to much fuel. Thanks

Tiny
Rob.kela
Jun 12, 2012.
Lift pump just supplies fuel to the injector pump. It sounds like you have injector issues.

Roy

ASEMaster6371
Jun 12, 2012.
Ok I just wanted to make shure I will order 450.00 In injectors for this thanks.

Tiny
Rob.kela
Jun 12, 2012.