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Warm start black smoke

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by RussCrypto, Dec 7, 2008.

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  1. RussCrypto

    RussCrypto New Member

    I've lingered here for a while, but this is my first post. Hopefully someone will have some ideas.

    I have a '99 C2500 Burb with around 80k miles on the 7.4L. A couple of weeks ago I noticed that on warm starts it will crank and crank before it starts up. Sometimes I'll have to pump the gas pedal a couple times. When it finally does start, there is a bit of black smoke that dissipates quickly. On cold starts, it turns over like a champ. No problems what so ever.

    Any suggestions?

    Thanks in advance!
  2. dwill3015

    dwill3015 Epic Member 5+ Years ROTM Winner 1000 Posts

    Welcome to the site! hopefully another member here with knowledge on the 7.4 will jump in and shed some light on your problem.
  3. 04sierracrewcab

    04sierracrewcab Epic Member 5+ Years 1000 Posts

    black smoke from a gasser??!!!?? :neutral:

    and by warm start you mean if you were to turn the truck off to order at a drive thru or sometihing?

  4. RussCrypto

    RussCrypto New Member

    Well, not exactly. It's more pronounced when after the truck has been driven enough to warm up, and then turned off for more than just a couple minutes, even up to a few hours.
  5. 04sierracrewcab

    04sierracrewcab Epic Member 5+ Years 1000 Posts

    when was the last time the fuel filter was replaced?
  6. RussCrypto

    RussCrypto New Member

    Just over a year and 15k miles ago.
    Last edited: Dec 7, 2008
  7. 04sierracrewcab

    04sierracrewcab Epic Member 5+ Years 1000 Posts

    hmm, well im not sure
    the black smoke does not come out when driving correct??
    and im not sure if it would help but may wanna change the filter anyway:neutral:

    somone else will chime in:great:
  8. RussCrypto

    RussCrypto New Member

    Correct, once running, there is no smoke. It's almost as if a choke plate were to get stuck on a carburated engine.
  9. 04sierracrewcab

    04sierracrewcab Epic Member 5+ Years 1000 Posts

    hmm, well could the fule pump be the issue?

    does it run fine when started?
  10. RussCrypto

    RussCrypto New Member

    It runs like a champ actually.

    Would a leaky fuel injector cause this?

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