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Thread: Black smoke

  1. #1

    Default Black smoke

    OK, took the new truck on it's maiden voyage over the holiday and noticed that even on small hills the truck would throw out a good amount of black smoke(in D with Tow/Haul mode activated).

    Shifting it into M and then manually shifting it into the next lowest gear would eliminate most of the smoke, but it was still putting out way more than the 03/04 Dmax in front of me.

    My 06 has the following, AFE Pro Dry S Stock replacement filter, and 4" Cat back exhaust. According to the original owner it has never had a performance chip on it.

    This is my first DMax, but I have had two Cummins trucks before this one, and normally when you increase air flow = less smoke. Do I need to have the dealer re-flash it to compensate for the increased air flow? What else could be the problem. There are no gages, so I can't see what my boost is, but the turbo sings pretty well with the AFE filter.

    CEL has not lit up, so I doubt there are any codes.

    Any ideas?

    Wade
    2006 3500 CC D/A 6 speed, long bed SLT 4x4

  2. #2

    Default

    Hello and welcome aboard TDP!

    I have owned two 2006 LBZs, and would describe the loaded performance, stock, as 'smoke-free'. Only with aftermarket tunes loaded have I seen it make visible black smoke.

    The logical thing is to eliminate 'what has changed' from this equation. Obviously, there is more fuel present than air to burn it - so you either have MORE fuel, or LESS air present than stock.

    If you are certain that there is NOT a leftover aftermarket tune left on the ECM, I'd look for a collapsing intake tube or air filter under high demand. I am a proponant of stock OEM air intakes on the Duramaxes in general, and even moreso on the 2006 with the HUGE, round improved filters that the General put on. Did you get the stock intake from the previous owner? An easy experiment would be to return to stock... Also, your idea of re-flashing the ECM to stock - with updates - would also eliminate the possibility of a leftover performance tune, if its still smoking with the stock filter back in place.

    Good luck!
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  3. #3

    Default

    I can only assume that the previous owner was telling me the truth, he traded it in on a dually and I bought it from the dealer so he would have no reason to lie.
    I could borrow my neighbors 08 filter and put in it for a test since it is only the filter it's self that was changed and not a complete intake kit.

    Does the 06 and 07 have a history of sucking in intake tubes? I'm not yet familiar with these engines enough to know. Is there any tale tale signs of tube collapse? I will take a look tonight.

    I pulled 10.9 mpg hand calculated 11.2 computer with 285 75 16 on it, pulling around 11K.
    I thought that was a bit low.

    Is there a programmer out there that will take a truck back to stock, or do you have to go to the dealer? I'm not looking for HP gains, the DMax should have plenty for my needs.

    Thanks Mark.
    2006 3500 CC D/A 6 speed, long bed SLT 4x4

  4. #4
    Join Date
    Apr 2001
    Location
    CA
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    Good idea to swap the air filter. Once they plug up (takes a LOT on the late models), it starves of air and can collapse the intake duct. Look for creases or inverted flutes (accordion ribs), or check immediately after a hard pull for the collapse. If no change, don't worry about the filter. Aftermarket element-only changes aren't really considered a "modification". With the 2006+ models, there's no reason to use any other than the OEM style element. There's just nothing wrong with them, at all.

    Other than that, you'll need to check the turbo vane servo and/or EGR function. They aren't necessarily "problematic", but do foul or fail, and prevent sufficient boost/air. The dealer can check its operation, a Tech II is required.

    If you need to reflash the PCM to OEM, only the dealer and a select few shops can do it (doesn't sound like you do). If you don't want/need an aftermarket program, don't. Some of them are very handy for tire size changes, though. The Predator programmer does this (and can add power if wanted, but not necessary), has a rather extended PCM parameter reading ability, and reads/clears DTC's, which could be helpful with your current issue. Some DTC's (Diagnostic Trouble Codes) are silent (no SES lamp) until the fault is serious enough, or has repeated a specific number of times over a given period, but the codes are still present in memory.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  5. #5

    Default

    I will get the codes checked also.

    Thanks
    2006 3500 CC D/A 6 speed, long bed SLT 4x4

  6. #6

    Default

    Quote Originally Posted by dctoner View Post
    >>> I pulled 10.9 mpg hand calculated 11.2 computer with 285 75 16 on it, pulling around 11K.
    Sounds pretty close to what I'd expect, even lower if the load has a large wind resistance, or if you have a heavy foot or expect speeds over 65mph.
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  7. #7
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,573

    Arrow

    Quote Originally Posted by Mark Rinker View Post
    Sounds pretty close to what I'd expect, even lower if the load has a large wind resistance, or if you have a heavy foot or expect speeds over 65mph.
    It may not be that good. Depends on if the tires size has been compensated.

    If the mileage is accurate, it isn't too far off the mark for the load. Add in summer temps and grades, and it isn't bad at all. It could be better, but the larger tires cost fuel. Driving habits have a lot to do with it, as well.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  8. #8

    Default

    I am used to 7-8mpg figures (loaded with tall and wide boats) so anything 9-10 sounds good!
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  9. #9

    Default

    Owner says that he didn't adjust for the tire size but GPS says the speedo is right on. The trip was mountainous so I don't think it did too bad especially for pulling doubles (28' TT and 15' ATV trailer)

    Will have more time to look under the hood tonight.
    2006 3500 CC D/A 6 speed, long bed SLT 4x4

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