HELP! Our newly purchased Duramax Hummer
 

Started making black smoke on a hill! Even on some fairly mild hills @ 70 MPH. Edge programer was set on economy.

we have owned it only 2 weeks, never did that before. only 9K miles on the Duramax. Then it started running normal again and has not done it in the 70 miles home. EGT was 1100-1200 during the smoke.

truck has ONLY been run on B99 since engine was new. we mixed in about 75% dino diesel shortly before the smoke issue???

It never smoked on B99, but it did after a mix of #2 and B99??

True. But it did not start smoking when we added #2 and has not smoked since that one incident. Lasted about ten minutes. We then continued our trip back to LA from Tehachapi (including some steep hills)

So it stopped after #2 was added?? Might have been some thicker veggie oil being burnt before the #2 had a chance to thin the mix out.

no. it did not smoke during hills/mountain driving UNTILL we ran some #2 and then it only did it for about ten min. on some hills. VERY black smoke and alot!

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sounds confusing. It never smoked for 300 miles or so ON B99. Then shortly (2 days) after adding about 80% #2 it had the smoking incdent. is that clearer?

Might have been some stuff that got separated out when the #2 and B99 mixed. I would recommend changing out the fuel filter(s). But after she cleared it's throat, so to speak, still runs strong??

possibly, but I thought it was an issue when you have been running #2 and then start Bio. This truck has been running B99 since new and has THREE fuel filters two of the are FASS?? Yes it is running strong again. Also we are only showing about 10-12 MPG on economy setting. Predator motorsports says we should be getting close to 22MPG. maybe another issue?

what year dmax motor is it?

or is it the 6.5?

It is a 6.6 I belive. With only 9K I would think 2006-2007

It you could please find out for sure. This way we can move to the proper forum. TIA. It have a little bigger/flatter front end have bigger headlights?? If so it's an 07 and up.

headlights? this is a duramax instaled in a HUMMER???

well even if it running on B99 with #2 its a diesel it will smoke! do you have a cat or muffler delete or is it the new LMM duramax with the EPA stuff if thats the case then it could have been into regen mode.

Did you have boost reading at this time of the black smoke and 1100-1200 EGTs?

post a picture of your engine and we can tell you what engine it is

They do not smoke even during regen :ph:. I cannot get mine to smoke with the PPE on the highest level.

well ive never seen my dads regen go off but on the 6.7 cummins my buddy has smokes when it goes into regen, its not black though just a grey color.

well it's def. a 6.6, also I checked the boots and they seem tight. How do I post a photo?

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His problem has to be over-fueling... Even if it is a result of improper boost.

Black smoke and high EGT's are from excessive fuel. My guess is gonna be that since it happened just once, your wastegate stuck open or something like that. Perhaps a computer glitch. It can't be a fuel filter issue, that would give you white smoke.

If it hasn't happened since, I wouldn't worry about it.

so how do I tell by looking if our 6.6 DM is the type that goes into regeneration mode?

Is it the new body style Duramax? If so then its an LMM with DPF

Oh dang I missed where it said Hummer.. is this a custom deal? You should be able to look at the exhaust and see a cat and a DPF and Muffler.. If you see all three, then it could be DPF regen..

It most likely does not have a waste gate if it is newer than a lb7, but maybe a vane positioning problem.

My Vane Position sensor went out on my LBZ.. and I knew right when it happened that something was bad wrong.. I lost ALOT of power except thru one small section of RPM..


Make sure nothing is blocking the air intake, clean the MAF Sensor.. See if you are still having the problem..

It won't have a DPF because they stopped building the H1 before the new regs took effect. I'm not sure if it's a LLY or LBZ though.

If it only happened once I would just monitor it for now. Maybe unhook your Edge next time and see if it gets better right away.

Hummer offered the 6.6 Duramax in the H1 "Alpha" for the 2006 and very early 2007 model years. According to Four Wheeler magazine: "In H1 trim, the engine makes 300 hp and 520 lb-ft of torque, a lead-foot-inspiring 46 percent and 18 percent gain, (over the 6.5L) respectively".

H1 Alphas were NOT equipped with a DPF and do not go into active re-generation mode, hence the reason he's able to run B99 in it and not ULSD only.

I question whether your Hummer is approved for bio-diesel use. Most newer diesels are approved for B-5 or B-10 at the most. I would definitely check to see if it's approved for Bio-diesel use and at what concentration percentage. If you take your Hummer in for a fuel related problem (like you just experienced) and the dealer finds un-authorized bio-diesel in the tank, they can, and will, void your warranty.

I've never heard of any Hummer getting 22mpg, even the Alpha. Low to mid teens seem to be the norm.

As far as your smoke and high EGT's, it could have been a sticking injector, the trans failing to downshift with the engine under excessive load, or a momentary sneeze in the computer.

Any codes stored?

My dad's '05 did this a couple of times, but it was accompanied by a loss of power and a little stuttering. He started to run the grey bottle of fuel additive (Diesel Service??)(from WalMart) through it, and he hasn't had any problems since. He runs B99 also. If he forgets to add his treatment to a tank, he usually only gets a quarter of the way through a tank before it acts up.

Ok lets see. It's an H2, 6.6 Duramax installed by Predator motorsports not Hummer.