My 2002 Duramax with 81K miles is running Banks exhaust and K&N air filter. It has a puff of black smoke at start up. Idle exhause appears clean. At any speed an increase in throtle causes black smoke until reaching speed. A heavy load causes worse smoke. I have cleaned the air filter, MAS, and replaced the fuel filter.

I use 4 oz Diesel Kleen with each fill up.

For $95 the dealer told me there were no codes and all pressures were good. Although the oil appears to be high on the stick ( 1/4") they said there was no fuel in the oil. A few day before the trip to the dealer, the check engine oil lite came on....

Need some direction.

An addition to the original post. The oil level turned out to OK :( I recleaned the MAS, no real improvement.

I could only see it being black if an injector was stuck open. Did you recently install the intake

Intake has been on several years. Would not an injector show up on the dealers tests?

Black smoke from a diesel under load usualy means your getting to much fuel for the amount of air the engine is getting. I would check your intercooler hose clamps to make sure they are tight also check for the famous hole in the intercooler line. On my truck we were looking for a performance issue and dealer pressure tested my intercooler and found that the factory welder had laid a perfect weld beside the seam in one 4 inch long spot on my itercooler. The factory spec. is 5lb drop in pressure in 15 sec. Mine was droping to 0psi in about 25 sec.
Also take your boost sensor out and very very very carefully tap it out to make sure there isn't a little foriegn material in it. don't stick any thing in it just a lite tap. If it has junk in it the computer could be getting a false reading. Hope this helps

x2 I never thought of that, It would have shown up in the tests too. I guess you could have them plug in the tech 2 and see what your boost is.

My 2002 Duramax with 81K miles is running Banks exhaust and K&N air filter. It has a puff of black smoke at start up. Idle exhause appears clean. At any speed an increase in throtle causes black smoke until reaching speed. A heavy load causes worse smoke. I have cleaned the air filter, MAS, and replaced the fuel filter.

I use 4 oz Diesel Kleen with each fill up.

For $95 the dealer told me there were no codes and all pressures were good. Although the oil appears to be high on the stick ( 1/4") they said there was no fuel in the oil. A few day before the trip to the dealer, the check engine oil lite came on....

Need some direction.

As an update, the above situation is with factory tunning. A recheck of the oil showed I was in error. Level is OK.

I dialed in an additional 50 HP causing all smoking conditions to get worse.

Appreciate any help from the pros!

Jim

its normal.Just extra fuel being sent out exhaust pipe.
the more fueling you add the more smoke you will see.
When I get "on" mine,it smokes like a freight train.:D