Engine/Transmission (1998.5 - 2002) Black smoke when shifting

[Nschroeder]

Hi I was hoping for my first post on here to be something good but im afraid that I may have a problemb starting to surface. I am kind of a newbie here so hopefully this question isnt too dumb.



What would cause black smoke to roll out of the tailpipe when letting off the fuel. It happens mostly when the truck was under hard acceleration and I go to grab the next gear. This past week it has been every shift when loaded no matter how soft i try to roll off the throttle.

 

[Boondocker]

Hi Nschroeder,

Welcome. Not much info to go on for diagnosing your problem. Filling in your signature about your truck will help and is generally interesting. How's your air filter?

Neil

 

[Nschroeder]

I have replaced the air and fuel filters since the onset of the problemb, neither of which helped at all. It does not smoke enough to see under power but as soon as I let off there is a small cloud of thick black smoke.

 

[16919]

I will sum this up in short... its normal. When you have a load on the motor you are building boost, as soon as you shift the load on the turbo goes down decreasing boost but leaves a bit of unburned fuel in the motor which comes out as black smoke.

Since you say your truck is still stock it should only be a little puff of black smoke, if it is enough that it is pitch black and you can't see the cars behind you then I would say that you might have other issues such as a boost leak or something..... by puff I mean maybe 2 foot by 2 foot square if you were to guess the size not 15 or 20.

 

[Nschroeder]

Thanks. It is definatley more like a 15 foot pitch black cloud that will obscure a car behind me. I will look into a boost leak.