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6.2 running poorly

Discussion in 'Diesel 6.2, Conversions Cummins, etc.' started by ridenby, Apr 14, 2021.

  1. ridenby

    ridenby Member

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    Engine was running well. It hasaGM8 turbo on it( previous owner). Started blowing black smoke, then grey with a little white every now an then. Lost a lot of power, to the point it barely pulled itself. Boost gauge read vacuum. Changed turbo out Still blowing smoke-maybe not as black,still grey, some white. low on power. Not sure of next move. It starts very well. Idles smooth. Goes funky at throttle. Help?
     
    MrMarty51 likes this.
  2. RecklessWOT

    RecklessWOT Full Access Member

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    6.2s aren't known to be the best diesels out there, my guess is it wasn't happy about the turbo.
    How much boost were you running? White smoke is most likely coolant. Have you checked compression? I'm guessing something cracked, or a catastrophic gasket failure at the least
     
  3. ridenby

    ridenby Member

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    I have had the truck for 3 years. Ran well until just recently. Boost never went over 5psi. It starts very well.
     
  4. Vbb199

    Vbb199 B-rate Hillbilly Customs

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    Sounds like cooked head gasket or cracked head
     
  5. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    I hate to jump on the blown head gasket bandwagon, but it's a possibility. You should be able to get a test kit to check for exhaust gasses in the coolant.

    It's also possible that pieces got into the engine when the turbo failed.
     
  6. Itali83

    Itali83 Full Access Member

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    It sounds to me like the turbo was never the issue and didn’t come apart. Therefore no pieces to go into the intake and damage anything

    Anyone who knows 6.2’s and have started them know that if ANYTHING is wrong with them compression wise, fuel wise, or anything they won’t start. The barely want to start on a 60 degree day. (A little exaggerated but you get the idea)

    white smoke on a diesel isn’t automatically coolant. If it smells sweet and you’re loosing coolant, odds are it’s coolant. But it’s starting fine so it’s not putting water in a cylinder from a cracked head or head gasket.

    completely unburnt diesel fuel will smoke white. Either from no compression (doubt it with his case) or injection timing (see where I’m going here?) I don’t claim to be a master wiz on these fuel pumps, never actually had one of these apart in my hands, but there is a timing advance unit built into them and I’m wondering(betting) this is the cause of the problem.

    if it starts fine, odds are all 8 have good compression(no catastrophic damage to bottom end). Loosing coolant( don’t know from description yet, but that’ll rule out head or gasket. As will the smooth start and no hydrolocking)

    check these things out and report back.

    Ben
     
    Last edited: Apr 15, 2021
  7. MrMarty51

    MrMarty51 Full Access Member

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    Prestone, engine coolant has changed formula over the last ten or twenty years. Unless the coolant has been in the engine for a very long time, it will not have that tell tale sweet smell to it.
    The coolant had a sweet taste to it that animals just loved. They would lap that stuff up until there was none left then die a very slow and painful death.
    The new green prestone now has a very bitter taste to it.
     
  8. ridenby

    ridenby Member

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    Went and pulled air filter off. Maybe a little less smoke. It is smoking at idle. Vac hoses and wires seem to be connected. Will get back to it later today.
     

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