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lots of black smoke and oily mufflers

Discussion in '1982-Present GM Diesel' started by chrisnjj, Nov 9, 2002.

  1. chrisnjj

    chrisnjj Registered Member

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    Hi, I recently purchased a 85 k-5 with a 6.2 and 700r4. It's in excellent condition and runs and drives great. Driving around town seems fine but when I'm on the interstate and hit any kind of hill it needs to downshift (3.08s) and can barely hold 45 mph on larger hills. I'm ok if thats all it has but just want to know if it's somewhat normal. It also shoots out black smoke when I give it any kind of throttle. It runs extremly smooth and idles perfect. It's like a smoke show behind me on any sort of hill. I checked underneath and mufflers look like they are leaking oil. Is this sort of power and smoking normal? I will change fuel filter and air filter even though they look recent. I have done a search and think it could be the cdr valve or egr? When I remove the oil cap or dipstick when it is idleing I don't see any blowby. Any advice would be helpful.
     
  2. Txstruck

    Txstruck Registered Member

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    Not sure about this one. I have an 86 K30 4x4 with a 6.2 and TH400 with 4.56 gears and it never loses any speed climbing a hill and doesnt even smoke! Well it will if I floor it and let the rpm's scream! /forums/images/graemlins/truck.gif
     
  3. Batmanjr

    Batmanjr 1/2 ton status

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    What size tires?? It makes a huge difference! I'm running a 6.2 700 4:10 on 33's and mine does the same thing!!!! /forums/images/graemlins/tongue.gif
     
  4. Txstruck

    Txstruck Registered Member

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    Mine are stock 33" tires. Its basically a stock military truck aside from the cb radio, K&N filter and the exhaust im getting ready to do. /forums/images/graemlins/truck.gif
     
  5. DieselDan

    DieselDan 1/2 ton status

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    The EGR set-up causes alot of smoke (at least in our older trucks). I disconnected the vacume line when I still had the EGR manifold and alot of the smoke went away. Oil in the exhaust usually is a sign of "slobber". Slobber from a diesel results from unburned fuel exiting from the combustion chamber, usually from excessive idling. Diesels don't burn much at idle - thus have cold exhuast temps until they start to work.

    How many miles on that puppy?
     
  6. chrisnjj

    chrisnjj Registered Member

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    Thanks DieselDan. So you just disconnected the vacum line from the egr valve and left it bolted to top of manifold? That would be really easy to do. I also noticed when I bought it that the grommet on the vacum line going to the egr through the air cleaner was out of place, so there has been a 1/4" gap of open dirty air entering the motor for who knows how many thousands of miles. Thats a good spot for anyone to block up if its open. The motor has 156k miles, mostly highway by the looks of it so I hope its not blow-by.
     
  7. Tybee

    Tybee 1/2 ton status

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    I put the J code manifold on and I still have an ass load of smoke out the pipes!
     

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