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What are all the causes, that make a carb make that Popping sound ????

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Silver84k5, Mar 8, 2002.

  1. Silver84k5

    Silver84k5 1/2 ton status

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    thx
     
  2. Stomp

    Stomp 1/2 ton status

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    popping where?
     
  3. lgk5

    lgk5 1/2 ton status

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    mine was to rich and not much back pressure
    to get it to pass i/m i had to jet it down and install a cat.
    now the popping is gone
     
  4. Blazer79

    Blazer79 1/2 ton status

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    Timing could be off. It doesn't hurt to check it.
     
  5. Twiz

    Twiz 1/2 ton status

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    Come 'awn, man. You want answers to that? We need info.

    Don't wast our time with a question without a discription.
     
  6. 55Willy

    55Willy 3/4 ton status

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    I talked to him on this and he is running a 850 Edlebrock Q-jet so it's BIG for the 350 he has. it falls on it's face.
     
  7. Twiz

    Twiz 1/2 ton status

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    So...
    Whats the details?
    Hows it run at idle?
    Cold start?
    Getting on the throttle?
    At freeway speeds?

    I'm not mad (but irritated, this happens too much)
    I'm just saying, If the guy wants a answer, ask a question. Not "What are all the causes, that- blah blah blah."

    If a guy wants questions answred, then he has to include the details, everything that could have anythig o do with the problem.

    It's hard enough to diag problems first hand, let alone over the "net".
     
  8. Silver84k5

    Silver84k5 1/2 ton status

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    it starts like crap, it seems like the secondaries never open up, it idles rough, i cant just stomp the pedal from a dead stop, itll just putter, i better just have somone look at it in person my bad
     
  9. chevyracing

    chevyracing 1/2 ton status

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    popping sound from the carb could be a sticky valve, exhaust lobe on cam going flat, bad lifter (collapsed), or about a billion million kazillion other things.

    John
     
  10. Highlander

    Highlander 1/2 ton status

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    I don't think I could List all the stuff that would do that, But what I will say is look for Vacuum leaks, Check your timing In short look at the Easy stuff first.

    Eric
     
  11. BorregoK5

    BorregoK5 1/2 ton status

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    Dont let everyone chase you away over a vague question, lets look this over. Were all here to share info, thats what this board is all about. If anything, it will make a good diagnostic thread.

    First off, you say its hard to start. Does it flood easily or do you have to pump it quite a bit to get it going? How did you determine that the secondaries never open, is this just a feeling you have or something you've deduced through process.. I ask this becuase a vacuum secondary carb won't open the secondaries unless its under load. So if your opening the throttle all the way with the engine off, your right, their not opening (same problem if your not in gear but revving it)

    The rough idle sounds like a vacuum problem, double check all your hoses and make sure their routed to the correct locations. This could also be timing related as mixture related so make sure you check these first before focussing in on the carb.

    As for stomping on the pedal and not going anywhere, how does it do if you slowly engage the pedal. If you can get the motor rev'd up and then stomp the pedal then your just trying to dump too much fuel too fast. If you get a flat spot in the pedal about half way down and then it picks up again, you need to adjust the spring on the top plate of the vacuum secondaries (ask before doing this, theres a trick).

    Throw back a little feedback from the questions above and I'll be more than happy to walk you through a few more scenarios we can check to figure out a remedy.
     
  12. Silver84k5

    Silver84k5 1/2 ton status

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    Ok i started messing with the carb today, and all i did was turn the screw on the driver side front of the carb, i dunno if this was A or F but the popping went away, and i can spin one tire when turning heh, (3.73 and 38"s is that prob) and the secondaries were opening when i was revving the motor thats all i can really say about it so far, i still want to mess with it more..... thank you
     
  13. BorregoK5

    BorregoK5 1/2 ton status

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    Sweet! Get a vacuum gauge on there and get it tuned in, sounds like your close though! Oh, and 3.73's on 38's..... I'll be you get great gas mileage! I relate though, 3.07's on 33's!
     
  14. Silver84k5

    Silver84k5 1/2 ton status

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    if there is a vaccum leak what do you do to fix it? just get new hoses or lines? tighten things up and what not?
     
  15. BorregoK5

    BorregoK5 1/2 ton status

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    Well, that depends on where the leak exists. I if this carb is a swap on and it ran fine before then that narrows it down a bit to the following.
    1. Carburator base - spacer plate gaskets.
    2. Manifold vacuum ports. Both on the carburator and on the intake. Follow all these lines to their respective destinations and follow them back out if that exist. Look for cracks in the tubing or the components they drive.
    3. Ported vacuum. This will be from the carburator out, sometimes to your vacuum advance. You shouldn't be able to blow or suck air through the vacuum advance canister.
    4. How are the brakes? If you can press the brakes and stall the engine you might have a leaking master cylender.
    5. Your carb might have case leaks (harder to track down).

    If the engine idles, you can try spraying a bit of carb cleaner around the base of the carburator away from any heat source or electrical spark. If the rpm's change, then you can isolate a leak at the base somewhere.

    Other leaks could occur at the intake manifold gaskets or air cleaner.
     
  16. Silver84k5

    Silver84k5 1/2 ton status

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    thx ill check it out ;]
     

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