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!

[MARK_VANDERBENT]

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.

[shakyjay]

Could be all of the above or could simply be a dirty MAF Sensor.

[MARK_VANDERBENT]

You all might not believe me, but I have been driving a lot of high mile duramax trucks. Many have had 300,000 plus miles, and have ran as good as ones with 100,000 miles. I drive high mile gas engines and they still run great after having over 250,000 miles on the clock. The 06 crew cab is a little riddin hard , but its performance and ride is still a 9 out of 10 with 300,000 on her. Black smoke at heavy throttle is all I experience, and I figured its been overfueled. I will try and find out if its been programmed.

[jason4598]

My older truck smokes bad occasionally. I think its a wastegate problem, but I'm not sure yet.

[Old-Biscuit]

donn0128 wrote:

gmcsmoke wrote:
per cummings197882v that engine has exceeded it's lifespan by 150k; a cummings on the other hand is only getting broken in and probably pulls better than new and goes up the grapevine 80mph getting 30mpg towing 28k pounds.

What is a cummings?
Mine says CUMMINS

He was a poet born in 1894.

[donn0128]

gmcsmoke wrote:
per cummings197882v that engine has exceeded it's lifespan by 150k; a cummings on the other hand is only getting broken in and probably pulls better than new and goes up the grapevine 80mph getting 30mpg towing 28k pounds.

What is a cummings?
Mine says CUMMINS

[2oldman]

-g

[gmcsmoke]

per cummings197882v that engine has exceeded it's lifespan by 150k; a cummings on the other hand is only getting broken in and probably pulls better than new and goes up the grapevine 80mph getting 30mpg towing 28k pounds.

[DirtyOil]

excessive black smoke = not enough air. Check air filter, turbo may be worn out. Then look at injector(s)it may have one or more worn out/stuck, adding too much fuel.

[bmanning]

Agree with the growing sentiment to take a pass on this one; you could be looking at thousands & thousands in repairs.

It'd be one thing if it was bone-stock and belonged to an old man who did tons of freeway driving & kept it pristine, but even then it could cost you.

I'd be more willing to buy a V10 or 8.1L with 300k; you could replace the entire engine for the same price as a fuel pump or injectors on the diesel.

Even then, you'd still have 300k on the trans, axles, front end components, etc.

300k is a lot on anything that isn't a class 8 truck. This may ruffle feathers but pickups, even 1-ton diesels, aren't truly designed to last like their commercial-grade big brothers.

[Engineer9860]

fatmanobx wrote:
injectors....

Injectors typically produce gray smoke, and will produce that smoke at all loads, and RPMs.

[norfla71]

Dirty fuel and/or filter all the way up to the injectors. If it were a Cummins I would say go for it; never have liked D-Maxes for longevity, unless you know and absolutely trust the seller (i.e. bought the truck new and has all service records). Otherwise, polite pass.

[Vulcaneer]

Think of it this way. If you put 50K miles on her and then try to sell it, Nobody will touch that truck with 350K on it. You won't be able to give it away. And that is if you can fix the smoking issue.

So you can spend an unknown amount to fix the smoke problem. But you are pi$$ing away your purchase price. And the repair price. That whole deal is a LOSER. You will get nothing back for your money.

And you haven't tried to haul anything heavy yet. You really haven't put the trans under stress yet. My bet is the trans is weak, too.

Spend more money for a less used truck. You'll be money ahead. And a whole lot less headaches.

I cannot help you with why the thing smokes. But that makes little difference. Other than to indicate there are unknown problems that are going to cost you more money in the future. It's Gods way of telling you to run away.

[The_Texan]

Ask yourself one question......Why is he selling the truck if it was such a good value :? Sorry, but there is something wrong, or this truck, which had to have been used in commercial service with that mileage, would NOT be for sale.

[2oldman]

Google: diesel blows black smoke