I have had a problem 3 times with my LBZ and need to know if anyone else has seen it. All times have been under some load with the engine warm. I will be driving and try to accelerate the truck blows black smoke and knocks. I am not talking about a little spurt of smoke, I am talking about a lot. Enough that the mechanic at the dealership noticed it in the pipe. When I say knock i dont mean like having bad fuel on a 4 cylinder engine. I mean it woke up a person sleeping in the truck.

I am not getting a code with this so the dealership has no idea what to fix. They said try fuel additive.

Also, when i am driving 65 and push my foot to the floor it takes 3 seconds to actually move the speedometer. My dad has an 02 and it takes off almost immediately. Again, no code so no fix.

I want to get this truck problem corrected so I can start adding stuff like aux. fuel tank and programmer but I dont want to do anything to the truck while it is having problems. It only has 6500 miles.

I can only compare it to my new LBZ with approximately 4500 miles. It is not normal. My LBZ is very responsive and runs extremely well. There is no smoke or knocking. I would stay after the dealership and not let them blow you off. If you are like me, you paid a lot for your truck and you should be able to enjoy it. Good luck !

how many times do you need to have problems for the lemon law to come into affect

Since they cant replicate the problem they say there is no problem found. They also show a bulletin that says to add Racor Diesel Additive. They see the buildup in the tailpipe so they know it has been smoking.

The rule in TX is 3 times for the same thing. I was close on my 2004 Ford. Funny story on that. First night I had it I got stuck after putting it in 4x4 and backing up 10 ft. Got out and saw a manual hub on drivers side. I was very upset. A manual hub on a Lariat. Got even more upset to find an auto hub on the passenger side. I have never seen more people come out of a shop to see a problem. I think everyone at the dealership had to come see it. Anyway, they replaced the hub, but it still didnt work, so they replaced both. The third visit they said they replaced the whole front drive train.

I dont know how to get them to take it seriously on the slow response. I guess we are going to have to pull one off the lot and take it for a drive. I am also upset about their solution being to add additive to the fuel. If the truck needs that they need to buy the additive or fix the reason it needs the additive.

They checked the injectors? I doubt this but, have you changed your fuel filter? How many miles on it?

I bet you have a intermittently bad injector. I may have one too...hard to prove when you aren't pulling codes. I bet if you put a program on there it will only exaggerate the problem.

Personally, I am going to try to call in a favor to my dealership and see if they will replace them, my problem is that i only get the knock sometimes and its only when i bump the rail pressure with the duramaximizer.

Just out of curiousity...is this only under moderate to heavy load?

Good Times....

I bet you have a intermittently bad injector. I may have one too...hard to prove when you aren't pulling codes. I bet if you put a program on there it will only exaggerate the problem.

Personally, I am going to try to call in a favor to my dealership and see if they will replace them, my problem is that i only get the knock sometimes and its only when i bump the rail pressure with the duramaximizer.

Just out of curiousity...is this only under moderate to heavy load?

Good Times....

If you are bumping the railpressure with your duramiximizer knocking is not a problem of the injectors.

Might have the first LBZ injector failure case for this board.

take it back to the dealer and insist that a tech with a scanner go for a ride with you so they can feel it they are obligated to investigate the problem if that oesnt get you results demand the number for your area rep and pitch a fit and or call the cust satisfaction line in your manual and start a case on it additive will not fix it you do have a fuel system problem.

Might have the first LBZ injector failure case for this board.
Second.
Diesel Tech had one go out at about 700 miles.

As far as the throttle response, my '06 LLY is the same. When I'm ready to pass someone, I firewall it and THEN pull into the passing lane. The BD tuner has helped, but the lag is still there.
It is much less pronounced if I roll into the throttle rather than slamming it to the floor.

May Be Poor Fuel Have It Cked
Also May Had Bad Fuel At One Time Or Another And Screwed Up Your Injectors, Fuel Pressure Regulator Could Also Cause This Concern None Of These Problems Have To Set A Code

i have 700mi on mine and see the same lag when i go to pass. it dosn't seem engine related as much as alli related i think the trans keeps the engine defueled untill the trans selects the gear it needs to be in before it will let the engine fuel up. i only say this because if you roll in to the throtle slowly it has all the power in the world. but when you smash it down its about 2-3 seconds to react.

I agree with geabis. I can feel the transmission searching for the right gear before it takes off. And, it does seem to defuel until it selects a gear. JMO.

If you are bumping the railpressure with your duramiximizer knocking is not a problem of the injectors.

Ok you have my attention. What is it then that causes knocking with the duramaximizer?

When my truck was new I thought it had VERY poor throttle respone. But a friend reminded the computer "learns" how I drive, now I love it & am very happy with the response, I now have about 2100, about 500 pulling our new "sand castle".

I do believe the new LBZ smokes more than my old '01 did when I put my foot in it. I'm guessing this is just normal, I sense nothing else wrong.

My only real "complaint" would be the ticking I get when I shut it down, fairly quickly after I turn the key to the off position. It's jsut kinda annoying.

Mine did that the first 2000 k, did it 3 times and hasn't done it since I now have 12000 k on the truck and it ROCKS

I agree with geabis. I can feel the transmission searching for the right gear before it takes off. And, it does seem to defuel until it selects a gear. JMO.

that sounds like what it is doing

It did it again, and adding the Racor additive made it better. I do not feel that this is a solution. If my truck needs an additive I feel GM needs to fix the problem that is causing it, or at least buy me a couple cases of it. They feel that it is an injector problem, but they are not willing to replace it because they dont get a code telling them it has failed.

I have also noticed that if I dont slam down the throttle it does take off all right. I am glad to hear that this is not just something on my truck.

I am trying to get this truck 100% because I need to put in my aux fuel tank and use a Superchip tuner when it becomes available. I know if I bring this truck in with a tuner and aux tank they will try to blame the problems on my adds.

i have some similar probs too. i got a real loud clunking sound like i dropped the motor, that bad, and some huge white smoke and stall. the first time it did it i was going about 75 mph down the road. the last 5-6 times it has been at a stop light. it feels like it is going to completely stall out. they cant figure it out. they gave me some fuel dry. i agree, i dont want to have to additive this beast its whole life.
then last weekend pulling a car trailer up donner pass 70-75 mph it rolled black smoke like i have never seen before. i told them i have driven my dad's 02 under the same circumstances and never black smoke. i have never even seen a gm puff black smoke. its at the dealer today for a few days i feel. we'll see.

Let me know what you come up with. That is the exact problem I had. I have only had white smoke the first time. Also, each time has been under load and at speed. I also noticed that the oil pressure looked low when it was happening, but I have seen other threads with others saying they thought it was low.

Ok you have my attention. What is it then that causes knocking with the duramaximizer?

If I have understand right duramaximizer only alters the signal of the rail pressure sensor so that the ECM controls a higher railpressure than normal.
Transient injection (diesel quantity over time during injection) becomes faster. Therfore the combustion is harder (knocking).
Suppressing knocking would need also a change in injection timing.
But duramiximizer doesn't change injection timing.

I took my 06 Duramax lbz on its first road trip this weekend pulling my 18' enclosed trailer. The truck has 900 miles on it and I was driving 70-75. On the way home I noticed heavy black smoke, so much that a pick-up caught up to me to tell me about it. Knowing there was nothing I could do about it, I kept driving because temp and oil pressure were fine. About 10 miles later it is still smoking and the it starts to rattle and knock. I back out of the gas and it quit, I gave it some throttle and it did it again. We turned off the interstate and I drained the fuel filter by taking the plug out of the bottom and pump the manual primer a few times to empty any water that may be in the filter. We took off again and made the rest of our trip (400+ miles) and it never knocked again, it still smoked like a train but other than that it ran great. Even at the time it was knocking it ran fine. I am hoping that I got some bad fuel, but I am still concerned about the smoke. MPG was around 8.5 driving 70-75 into a strong head wind and 9-10 with no wind.

mine doues the same thing,could this be the turbo spooling up? so no power till the vanes close