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black exhaust crap

Discussion in 'General Tech and Maintenance' started by preludebuddy, Nov 18, 2004.

  1. preludebuddy

    preludebuddy Senior Member

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    hey guys, i've seen exhausts shooting out a bunch of black shit when they shift. I never really knew what it was...some sort of carbon shit? anyway i always thought it was gay, well my new car is doing the same thing. i can see it all over the back of the car. how the hell do i stop it from happening?
     
  2. swanny

    swanny Senior Member

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    Do a compression test first and get back to us with the results. It may be rings, valve seals or somethin simple like your running rich.
     
  3. preludebuddy

    preludebuddy Senior Member

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    i know the valves need to be adjusted, but i'll check into the compression test too.
     
  4. webink_EK9

    webink_EK9 Senior Member

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    paint the car flat black and you can't see it anymore.

    How do you adjust the valves? I need to do this to stop the clicking noise I've had. Have you done it before?
     
  5. pissedoffsol

    pissedoffsol RETIRED

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    running rich, burning oil

    neither is good
     
  6. YouKnowWhoIBee

    YouKnowWhoIBee my avatar is better.

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    The clicking noise in dohc vtec motors is common and doesnt always mean that the valves need to be adjusted. It maybe caused by the loss motion assemblies and is totally normal.
     
  7. Mohsin

    Mohsin Junior Member

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    iv got a similiar problem, my car is clearly running rich, exhaust is black, i can smell a strong smell of petrol is well, not to mention loss of economy. Would it be the Air/Fuel ratio sensor? IF not whats the cause of running rich.

    Thanks.
     
  8. friz

    friz Senior Member

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    Running rich, If it's only happening during shifting it is possible that the injectors are still pumping fuel in to the intake when the throttle is rapidly closed causing a temporary rich condition at shifting. Oil burning creates a blue smoke, so this is not the cause. You might ask some these tuning hotshots if there is a way to take care of this.
     
  9. 94RedSiGal

    94RedSiGal Senior Member

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    True that, but an engine is much safer running rich (cooler) than running lean (hot).
     
  10. friz

    friz Senior Member

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    Not necessarily true. The excessive fuel in the cylinders washes down the cylinder walls and keeps them from being lubricated as well. Thats one of the reasons that modern fuel injected engines last longer. Older engines had in inefficient choke mechanisms that dumped large amounts of raw fuel in intakes during a cold start. These had to be eliminated for modern autos to meet emission requirments. In a way we can thank government intervention for our modern and efficient fuel injection systems and longer lasting engines.
    :D
     
  11. 94RedSiGal

    94RedSiGal Senior Member

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    Okay. Of course we don't know if the thread starter has a stock setup or a modded one... but speaking from my experience with my Si, someone with a turbo'd VW and another person from Boston who was in Road Atlanta two months ago at a World Challenge race in an ITR, running lean is BAD. Running lean in my Si with the wrong Spoon ECU for my car, toasted my exhaust valves badly. In the the VW, datalogging with a wideband O2 sensor caught the problem in time. In the ITR, they lost two engine blocks from running it too lean.

    Depending on what's going on under the hood of that car, ECU tuning can correctly solve the A/F problem.
     
  12. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    :shrug:
    my car has no problem running A:F ratios of 25:1
     
  13. pissedoffsol

    pissedoffsol RETIRED

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    :worthy: :worthy: :worthy: :worthy: 144 volts :D


    lean, rich, its all bad.

    gett'er tuned.
     
  14. liquid00meth

    liquid00meth Senior Member

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    I'd take rich before lean, but it still aint't right. Your motor just might be spitting carbon. My engine with 150k miles, spits black if I drive it hard. Thats just the carbon build up being spit out.
     
  15. sohcslammer

    sohcslammer Senior Member

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    Finally. :D

    Old hondas spit out carbon build up all the time. Make sure that it's black though. My car was spitting out smoke and I thought it was black, but that was because my CEL was on and it was running rich in limp mode. In reality it was blue smoke. :(
     
  16. preludebuddy

    preludebuddy Senior Member

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    its definately black carbon stuff its spitting out...no blue smoke. the motor has 80,000 miles on it so its not like its old or anything. I'm just gonna have someone check it out. thanks for the input.
     
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