[aglinks]

Hey all,

2006 Cummins with a rebuilt engine (25k miles so far). The truck runs great, but smokes more than I like until the boost kicks in. When accelerating, the first 2 seconds or so I have black smoke (not coal rolling, but still). The truck has a 4 inch exhaust with an unbranded muffler and no CAT (not my choice, that's how it came to me). Will re-installing a CAT fix this? I dont want to be branded a coal roller so the less smoke the better!

 

[Gildo]

My 07 has always done that when accelerating in a low boost situation.

 

[cerberusiam]

If you drive not like you stole it, when you jump on it the muffler will clear of soot, that is normal. No, CAT will not stop that. It will still happen when you blow the soot out.

 

[aglinks]

I definitely don’t drive like I stole it. My wife says I drive like a grandma lol

 

[MDSWA]

Do you have any modifications to your truck that could be contributing to the smoke? Are you running a tuner, larger injectors, aftermarket turbo? Some easy things you can check; air filter clean? IAT (intake air sensor) clean, MAP sensor clean? Pull and spray with MAP sensor cleaner. Are you running new injectors? stock, remans? Worn or defective/damaged injectors can smoke like crazy. Remans often fail right out of the box. Pull intake tube off turbo and check shaft for excessive play. Wiggle the turbo shaft side to side. Should be very little radial play. Push/pull the shaft straight in and out. Should be tight with no play. Do a few WOT passes on the highway to see if you can blow the accumulated soot out and see if it clears. Driving slowly around town tends to build up soot in the exhaust system.

 

[aglinks]

Do you have any modifications to your truck that could be contributing to the smoke? Are you running a tuner, larger injectors, aftermarket turbo? Some easy things you can check; air filter clean? IAT (intake air sensor) clean, MAP sensor clean? Pull and spray with MAP sensor cleaner. Are you running new injectors? stock, remans? Worn or defective/damaged injectors can smoke like crazy. Remans often fail right out of the box. Pull intake tube off turbo and check shaft for excessive play. Wiggle the turbo shaft side to side. Should be very little radial play. Push/pull the shaft straight in and out. Should be tight with no play. Do a few WOT passes on the highway to see if you can blow the accumulated soot out and see if it clears. Driving slowly around town tends to build up soot in the exhaust system.

The truck is a stock rebuild, no tuner, new stock injectors, stock spec turbo. I just replaced the air filter with a WIX 49946 but that didnt make a difference. I will check the IAT and MAP this weekend and see how they look. Once I drive on the highway the first WOT pass blows some smoke but its all clear after that so it might be just soot accumulation when driving around town.

 

[ShaunM]

I wouldn't describe my driving habits as grandma but I too like to stay on the conservative side. Despite that, I routinely see a steady smoke that I can best describe as haze on acceleration. It's not thick at all. It might be normal but MDSWA has me thinking about my air filter. Its been a while since I cleaned it so I wonder if that'll make a difference. I'll get back to y'all on that

 

[cerberusiam]

Definitely check the air cleaner and then watch carefully when driving. If you see a grey haze or even a light have any time you accelerate, hard or just semi-aggressively, you have injector issues. The haze is one of the first indicators of issues.

 

[aglinks]

Definitely check the air cleaner and then watch carefully when driving. If you see a grey haze or even a light have any time you accelerate, hard or just semi-aggressively, you have injector issues. The haze is one of the first indicators of issues.

How would I check my injectors?

 

[cerberusiam]

That is the question, how to check for injector problems. IMO, you don't even try, buy a set and go from there. If you have no info on what was used for injectors in the rebuild then you start over with a known product.

 

[aglinks]

That is the question, how to check for injector problems. IMO, you don't even try, buy a set and go from there. If you have no info on what was used for injectors in the rebuild then you start over with a known product.

I would say there is haze when I first start is in the morning. It clears after a second or so and I dont notice any when driving.

 

[cerberusiam]

Check closely when driving and hard accelerating for a have after up to operating temp. Haze at idle unless it is cold is not really a good thing either.

 

[aglinks]

Check closely when driving and hard accelerating for a have after up to operating temp. Haze at idle unless it is cold is not really a good thing either.

It has been cold enough in the mornings that my intake heater cycles.

 

[cerberusiam]

Hmmm, cold in Cave Creek AZ?? Are you somewhere else?

Grid heater doesn't cycle until the temp drops under 60 degrees. I almost never see a haze unless the temps are well into the 20's or even teens. Even then it is mostly condensation not fuel haze.

 

[aglinks]

Hmmm, cold in Cave Creek AZ?? Are you somewhere else?

Grid heater doesn't cycle until the temp drops under 60 degrees. I almost never see a haze unless the temps are well into the 20's or even teens. Even then it is mostly condensation not fuel haze.

Oh! I live in Flagstaff, AZ. It's been in the high 30's at night at my house recently. Thanks for the reminder, I updated my profile just now. It even has the right truck now.

 

[cerberusiam]

Ok, that makes sense.

Is the smoke fuel or condensation. that is my first question?

 

[Gildo]

The truck is a stock rebuild, no tuner, new stock injectors, stock spec turbo. I just replaced the air filter with a WIX 49946 but that didnt make a difference. I will check the IAT and MAP this weekend and see how they look. Once I drive on the highway the first WOT pass blows some smoke but its all clear after that so it might be just soot accumulation when driving around town.

I've never subscribed to the soot in the exhaust system theory. Mine will repeatedly blow smoke anytime I get on the throttle pretty hard in a low boost/slow speed situation, until the rpms come up an the engine starts burning the fuel that I'm putting into it. If I then get on it hard again, but in a high boost situation/high speed condition, of course it doesn't blow as much smoke because in a high boost situation more of the fuel is being burned than in a low boost situation. But I can slow down to a low boost/low speed condition, or come to a stop, get on it hard and it will blow smoke again, every time, always has.