Excessive black smoke from diesels means ????

[MARK_VANDERBENT]

I guess I thought that heavy black smoke from diesels was from over fueling the pump?? but I am not real sure.I am looking at an 06 duramax crewcab with 300,000 miles, and it runs awesome and idles with out any haze, but when you get on it , it lays coal pretty good. Is this something I can deprogram ?? or is this a turbo thing?? I can get the truck for around 10 and it runs so great other than the black smoke when I get on her. Thanks for any insight!

[Wiley75]

Gemstone wrote:
When I was in mile high Denver for a summer season, my Dodge Cummins started to smoke so bad I took it in fearing injectors were bad. Took it to an independent shop, they found nothing wrong (a "stealer" would have claimed the injectors needed to be replaced). Once I returned to sea level the smoke stopped.....and I always heard that elevation made no difference to a diesel. And the engine was chipped at 20K, I now have just shy of 200K, with no issues, and the original injectors....that said, I too would suggest looking for a truck with less than 300K miles.

Regards
Gemstone

Yep. Unfortunately diesel engines are not exempt to the laws of physics. Modern engines can correct some for this with variable geometry turbochargers, wastegates, and so on. But only to a point. A little black haze is normal to see during heavy throttle applications at high altitude, especially when it's warm outside (which lowers the air density even futher).

[mtofell1]

MARK VANDERBENT wrote:
A full scan of the truck show no program on it.

I'm pretty sure with that year Dmax once the tune is taken out and the computer reset it shows no trace. The newer ones store the history but the old ones people can still fool the dealer..... and buyers. Just food for thought while shopping. There are other signs of tuners you can look for. Things like gauges or holes in pillar where they once were. There are also places under the hood where you can check for holes various probes and such made. dieselplace.com has a lot of good info. Keep looking.... these are GREAT trucks.

[MARK_VANDERBENT]

A full scan of the truck show no program on it. He just put 2 new glow plugs in it and there is no check engine codes on computer. I do feel that this truck has been used for over the road hauling , I know that is probably not a good truck to buy second or third hand, it just runs so good other than the black smoke on heavy throttle. I thank you all for your imput and do believe I should check out another truck. I am really watching midwestdieseltrucks.com they seem to have some unbelievably clean high mile duramax trucks for around 12,000 thanks again!

[Tystevens]

tluxon wrote:
Advice asked for is not always advice taken. The OP may have simply wanted to see if he could be talked out of doing what he was thinking of doing. SOMEbody's going to end up buying that truck and taking their chances. Why not him?

Vulcaneer wrote:
...Ever wonder why someone traded it in?

There are numerous reasons, with many of them being no cause for concern. Perhaps the previous owner cashed in on something and decided to trade this one in for a new truck. People don't always keep vehicles just because they were in too good of shape to unload.

Agreed. We got rid of our perfectly good LBZ Duramax due to a 4th child arriving. Nothing at all wrong with the truck, and I thought I'd keep it another 50k miles at least, but, well ... turns out we needed a new Suburban instead!

Still not sure if I like the 4th kid or the Duramax better!

[Tystevens]

larry barnhart wrote:
When we drive around Casa Grande AZ during the winter months and then drive on I-10 and I hit the throttle hard we get black smoke but it is not for long and then I can not get it to smoke if I do it again. Nothing new just a diesel doing what diesels can do.
chevman

Yep, my '06 Duramax would blow a little cloud of black smoke if I hadn't gotten on it in a few days. It would last for a second, maybe (ie, getting on the freeway on-ramp),and then wouldn't smoke anymore no matter what I did. Just had to blow some stuff out every so often, I guess.

[tluxon]

Advice asked for is not always advice taken. The OP may have simply wanted to see if he could be talked out of doing what he was thinking of doing. SOMEbody's going to end up buying that truck and taking their chances. Why not him?

Vulcaneer wrote:
...Ever wonder why someone traded it in?

There are numerous reasons, with many of them being no cause for concern. Perhaps the previous owner cashed in on something and decided to trade this one in for a new truck. People don't always keep vehicles just because they were in too good of shape to unload.

[Vulcaneer]

MARK VANDERBENT wrote:
I am wanting to find out bad because this truck is sweet in my book! It is the sought after year engine and wow does that truck go!! Idles all day like silk and zero haze !!! Just blows black smoke when moderate accelerate. Cold ac, smooth ride, tight front end, no leaks on ground, 4x4 works normal, so we shall see.

So you have made up your mind. Makes me wonder why you even asked. So ignore those that have tried to help. Enjoy your new truck. Your gunna love it. What could possibly go wrong? Ever wonder why someone traded it in?

[larry_barnhart]

When we drive around Casa Grande AZ during the winter months and then drive on I-10 and I hit the throttle hard we get black smoke but it is not for long and then I can not get it to smoke if I do it again. Nothing new just a diesel doing what diesels can do.
chevman

[ib516]

64thunderbolt wrote:
That Dmax has a tune in it of some type. If it idles fine but smokes when you stand on it I would bet $$$$$$ it's either programmer or tuner.

x2

[transamz9]

64thunderbolt wrote:
A friend has a 7.3 with twin pumps, big inj, & 38r turbo. 270K and still runs great. Using them without abusing them is the key if tuned. Mine has been tuned since 100K. Now 157K+. Just have to use common sense. Not knowing the history I would stay away from it.

X2

[64thunderbolt]

A friend has a 7.3 with twin pumps, big inj, & 38r turbo. 270K and still runs great. Using them without abusing them is the key if tuned. Mine has been tuned since 100K. Now 157K+. Just have to use common sense. Not knowing the history I would stay away from it.

[carringb]

64thunderbolt wrote:
That Dmax has a tune in it of some type. If it idles fine but smokes when you stand on it I would bet $$$$$$ it's either programmer or tuner.

Yup. And be prepared for a huge letdown when it goes back to stock. With that many miles, no way will it still run like new if that tuner has been on it for a while.

[64thunderbolt]

That Dmax has a tune in it of some type. If it idles fine but smokes when you stand on it I would bet $$$$$$ it's either programmer or tuner.

[2oldman]

Did you click the link I provided? I'm sure there's more info that just on here.