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lot's of black exaust smoke when I stomp on it.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by gotmud?, Apr 18, 2002.

  1. gotmud?

    gotmud? 1/2 ton status

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    lot\'s of black exaust smoke when I stomp on it.

    only happen's first time I stomp on it once a day..usualy when i'm getting on the highway..tip of tail pipe is all sooty too.....running to rich? 154K 305/quadrajet oh yea it only blows this smoke for 5-10 secs but sometimes it's a pretty good size cloud. ran some techron thru it but still does this.
     
  2. NITRO

    NITRO 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    just dont drive like grandma so often and it will prolly stop. usually, its just burning off carbon deposits. i wouldnt b 2 worried.

    NITRO
     
  3. 90K5

    90K5 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    pour some ATF down the carb. That'll break up the carbon. Then watch and see if it continues to do it.
     
  4. gotmud?

    gotmud? 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    foot's alway's in it so it ain't from driving like granny
     
  5. gotmud?

    gotmud? 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    thought that's what that $10 dollar bottle of techron was supposed to do.
     
  6. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    I have never heard of putting the ATF down the carb. I have heard of putting it in the oil fill hole, and PCV hole to get the carbon to break off the valves. This of course is with the engine warmed up, and right before an oil change.
     
  7. shane74

    shane74 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    This is what you can do if your worried about carbon. Put some ice water in a spray bottle, like what you use for window cleaner, and mist it over the top of the carb after the rig is warmed up. You'll have to work the throttle as you do this to keep from stalling it out. As the cold water hits the hot piston chamber, the carbon will flake off and you should see a bunch of black flecks come out the tail pipe. That's you're carbon build up. If it keeps doing it, run a half tank of Av-gas mixed with a half tank of premium. If it still smokes, you need a valve job and/or piston rings.
     
  8. NITRO

    NITRO 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    he sayed he wanted to get rid of the black smoke, not his engine. I run seablue 114 avgas in my 555cid race truck and if u mix too much of that [censored] in, u'll burn up the carbon and the valves, and the rings, and etc. It really shouldnt b n e thing to worry about. check compression and see what it is. this will hint u on a rebuild or otherwise.

    NITRO
     
  9. gotmud?

    gotmud? 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    that's why I'm wondering if running to rich will cause carbon to build excesively. and if this is a symtom of running rich,cause I ran 2 bottles of techron thru it and allways burn premium.
     
  10. gotmud?

    gotmud? 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    Grim, you got an opinion on this?
     
  11. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    My Dad used to run AvGas in his Harley Davidson when he was in the Navy. If he was almost out of gas, he would borrow some of the test samples of the AvGas, and dump them in his gas tank. He said he had to drive to the nearest gas station, and fill up his bike that way he didn't burn out the top end of his motor. He only did this when he didn't know if he would have enough gas to get to a station though.
     
  12. shane74

    shane74 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    That's why you mix it. I had a 420 h.p 327 that would ping like a mother if I didn't run av-gas mixed with super. Just so ya know, that techron stuff and all the other "cleaners and octane boosters" really don't work on an engine that has that much build up. I wouldn't say run av-gas on a regular basis unless you had an engine built to handle it, but it will help clean out an engine that has a lot of build up. But those are some tricks I was taught by guys who have been in the drag racing industry for years. The cold water thing is basic chemistry in action.
     
  13. shane74

    shane74 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    Yes, it will cause build up. The best stuff on the market for a "drop in cleaner" is either the Slick 50 stuff or the Gumout fuel injection cleaner. The rest of them are very diluted and work well as a preventative maintenance, but not as a serious cleaner. The techron stuff isn't worth the money.
     
  14. riz

    riz 3/4 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    <font color=blue> Good to know ... also, nice tip on the spraying water around the carb.
     
  15. 90K5

    90K5 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    Premium burns quicker than regular. Unless your engine pings with 87, try that and see if it goes away...its probably ok for your old 305 with that many miles on it anyway...plus it saves you money.
     
  16. gotmud?

    gotmud? 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    ping's like a mother on regular, wish I could use it!
     
  17. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: lot\'s of black exaust smoke when I stomp on it.

    When's the last time you did a tune-up and checked your timing? I have a 305 with similar mileage and have no problems.....
     
  18. morphed86k10

    morphed86k10 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    the 305 in my 86 pings like a mother on 87 too..and I'm sure the timing correct and the rest of the ignition is in good order. It has the high altitude emissions, wonder if that has anything to do with it?
     
  19. Blue85

    Blue85 Troll Premium Member

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    Re: lot\'s of black exaust smoke when I stomp on it.

    I was going to say the same thing, maybe the problem is the premium fuel. Premium burns slower, though, that's why it doesn't ping.

    gotmud,
    How about cutting the timing back a little and running midgrade or regular?

    If you get black smoke, that's either carbon or fuel. If it was oil leaking past, that would look blue. Since it only puffs when you first step on it, the easiest thing to check would be adjusting the accelerator pump linkage to fire a smaller shot of fuel. After that, you might need to look into rejetting the carb. But really, if this is a fairly stock engine and it needs premium, there is something wrong.

    Stock, these things are lucky to be as high as 8.5:1, some are under 8.0:1. It should run at sea level on low octane gas from the mountains.
     
  20. speed_deed

    speed_deed 1/2 ton status

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    Re: lot\'s of black exaust smoke when I stomp on it.

    Just what you said!! It works as a steam cleaning job.
     

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