Black smoke and bad fuel economy

MRQP1 · July 12, 2005

I have 1 2004 crewcab dually with an early LLY engine. It has 32000 miles. About 3 months ago the fuel economy started to go down and LARGE clouds of black smoke would come out my exhaust under hard acceleration. It is worse when I tow boats. The smoke is so bad I cannot tell what kind of car is beside me. I have taken it to the dealer 3 times and they cannot find the problem. Help! PS: The truck has a Gibson Cat back exhaust and a K&N air cleaner since 5000 miles. I have not installed any computer reprogram kits.

16gaSxS · July 12, 2005

I have 1 2004 crewcab dually with an early LLY engine. It has 32000 miles. About 3 months ago the fuel economy started to go down and LARGE clouds of black smoke would come out my exhaust under hard acceleration. It is worse when I tow boats. The smoke is so bad I cannot tell what kind of car is beside me. I have taken it to the dealer 3 times and they cannot find the problem. Help! PS: The truck has a Gibson Cat back exhaust and a K&N air cleaner since 5000 miles. I have not installed any computer reprogram kits.

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I don't know much about DuraBux trucks but black smoke is caused from unburned fuel, that can be caused by Turbo system not working right like a INOP or stuck wastegate or controller, the Turbo could be the problem too (unlikey) or over fueling. By guess is something with the Turbo, try another dealer see if you can find "THE" Diesel dealer in your area.

Silverado4x4 · July 13, 2005

Could be your m.a.f sensor in your air intake,ive read about them getting oiled up over time from running the kn air filter and screwing with the air fuel mixture

DMAX-MIKE · July 26, 2005

Exactly what i thought !

willieboy · July 26, 2005

I am guessing it is the turbo also. Try and different dealer and have them check the vac lines going to the turbo. One of them is held on by a substandard clamp, and falls off occasionally. It happened to my father-in-laws Duramax at about 50K. He had the exact same symptoms as you.

MRQP1 · January 18, 2006

This is an update to my problem. I have taken the truck to my local dealer 5 times, then I took it to a different dealer, they told me nothing was wrong, then I took it to West Coast Diesel Performance. Their tech showed me within minutes on his scan tool what was wrong. Number 5 injector was bad. He called Lake Chevy. The truck went there, their tech said nothing was wrong. The owner and the tech from West Coast went to Lake Chevy and showed them on "their" scan tool what was wrong. They said oops! They replaced the # 5 injector and now everything works normal. I find it hard to believe the truck had to go to 3 GM dealers, it was at dealers for a total of 3 weeks off and on, and I had the problem for 18000 miles and 6 months. And then it took a " hot rod guy" who does performance upgrades to diesels to find the problem! Then he had to show them how to diagnose the problem!

Durymcgee · January 25, 2006

Yea dealers are dumb, check out dieselplace.com if you have any more problems, that forum is all dmax/gmdiesel.

nalineeds24s · April 12, 2006

This is an update to my problem. I have taken the truck to my local dealer 5 times, then I took it to a different dealer, they told me nothing was wrong, then I took it to West Coast Diesel Performance. Their tech showed me within minutes on his scan tool what was wrong. Number 5 injector was bad. He called Lake Chevy. The truck went there, their tech said nothing was wrong. The owner and the tech from West Coast went to Lake Chevy and showed them on "their" scan tool what was wrong. They said oops! They replaced the # 5 injector and now everything works normal. I find it hard to believe the truck had to go to 3 GM dealers, it was at dealers for a total of 3 weeks off and on, and I had the problem for 18000 miles and 6 months. And then it took a " hot rod guy" who does performance upgrades to diesels to find the problem! Then he had to show them how to diagnose the problem!

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I would file a complaint with GM, and tell them what was going on. Sometimes for your trouble they will give you discounted, or free GM accessories, and will be a “black mark” on your dealer.

bzingre · April 16, 2006

Check you intercooler boots. Black smoke = to much fuel, or not enough air. Could be plugged air filter, bad injector, or damaged turbine, or maybe a wastegate.

brady · June 30, 2006

Exactly what i thought !

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I have had a similiar problem with this sensor. I brought in my truck because its idoel jumped when in park or in traffic. Dealer said this sensor was coated with the oil from my k&n filter. still does it, i assumed he is right because when i charged my filter this last time i believe I may have used a little too much oil.

duramaxHD · July 6, 2006

then I took it to West Coast Diesel Performance.

Clyde is the man!!!!

KICK · July 22, 2006

I find it hard to believe the truck had to go to 3 GM dealers, it was at dealers for a total of 3 weeks off and on, and I had the problem for 18000 miles and 6 months.

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If U knew what I know about Diesel engines you wouldn't find it all that hard to believe.

figure the average tech at a GM dealer might know something about fixing cars and light trucks with gasoline engine... key word "Might Know".

then factor in Diesel, which is maybe 10% of the trucks the General sells and services and the knowledge factor is going to be way down.

If I had a Dodge with an ISB and I had an issue, I'd be taking it to a Cummins dealer to get it fixed. Not the Dodge dealer.

Same for Powerjoke engines. International dealer is the place to go.

OnyxMAX · August 10, 2006

yea it sucks, you either have to take time off or be special ed (or name of bosses buddy) to get to go to the classes the big three offer, for new stuff.

workinallthetime · June 15, 2007

I find it hard to believe the truck had to go to 3 GM dealers, it was at dealers for a total of 3 weeks off and on, and I had the problem for 18000 miles and 6 months.

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If U knew what I know about Diesel engines you wouldn't find it all that hard to believe.

figure the average tech at a GM dealer might know something about fixing cars and light trucks with gasoline engine... key word "Might Know".

then factor in Diesel, which is maybe 10% of the trucks the General sells and services and the knowledge factor is going to be way down.

If I had a Dodge with an ISB and I had an issue, I'd be taking it to a Cummins dealer to get it fixed. Not the Dodge dealer.

Same for Powerjoke engines. International dealer is the place to go.

ohh the stories i could tell about other dealers and d-max. best bet is to find a dealer who sells medium duty trucks and services them to get your d-max fixed and then you might get it fixed,lol.

i once had a basket case droped in my bay. 02 d-max pass side head off and all the parts in the floor and bed. the guy was told the head and block were both warped. i checked that thing every which way and could not find anything wrong. his original complaint was smoking and losing coolant. so i put it all back together with new injectors and found the coolant leak to be a leaking heater core hose and the smoke was from a bad injector.

this was bad for the customer because it was all customer pay and i charged 30 hours for the mess i was handed and the guy had to pay the other dealer who tore it down 1500 for the teardown.

the kicker is the only thing the guy should of had to buy was a 35.00 hose.

THERE ARE TECH'S THERE ARE MECHANICS AND THEN THERE ARE GUYS WHO FIX THE TRUCK !!