93 GMC 3500 6.5 diesel smoking problems/questions..

Discussion in 'GMC Truck Forum' started by 93gmc, Aug 5, 2009.

  1. 93gmc

    93gmc New Member

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    i have a 93 gmc 3500 with 6.5 turbo diesel and it has around 150,000 miles on it. and when i start it up in the morning it starts up but chugs and blows blueish white smoke and will then if i hit the throttle it still chugs and blows smoke, then evens out after a few minutes. Would injectors be the problem? or what are your guys opinions. any input would be great. then after its warmed up and i start it up it doesnt do it, its only when its been sitting over night.
     
  2. bradrhale

    bradrhale Senior Member

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    maybe the injectors leaking down over the course of the night. i have had similar problems on a bit of a bigger scale, but might still apply to you in your application.
     
  3. 93gmc

    93gmc New Member

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    thats what i was thinking. and once its warmed up and you rev it up it'll blow black smoke but is then followed by a puff of blue. i was wondering if i might just have one bad injector or what. any input?
     
  4. bradrhale

    bradrhale Senior Member

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    really wish i could give you a bit more information than that, but we ended up trading off that truck before we got to fix the problem. it could very well be just one injector but the chances of it being that one are slim. maybe one of our resident diesel guys will chime in here with a bit more info.
     
  5. BernieB

    BernieB Senior Member

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    If it's the injectors running a can of Seafoam or Diesel 911 through it might help, and sure won't hurt.
     
  6. NCroadracer

    NCroadracer Senior Member

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    Sounds more like slightly worn valve guides, with the puff of blue smoke n all.
     
  7. 93gmc

    93gmc New Member

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    thanks guys, does anyone have any ideas on what i should do?
     
  8. tripower428

    tripower428 Full Member

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    I have a 94 chevy 3500 with the 6.5 diesel and have the exact same issue. What I am trying right now is some injector cleaner, (I used diesel kleen). I used a 16oz bottle with my past tank of fuel. I don't yet know if this will help or not, If not I think I have a bad injector. The injector cleaner is cheaper than replacing any injectors. You may want to try it. I hope this helps.
     
  9. Square357

    Square357 Full Member

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    How difficult would it be to replace valve guides?
     

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