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surging, carb issue?

Discussion in 'The Garage' started by MTChevy, Jan 23, 2006.

  1. MTChevy

    MTChevy 3/4 ton status Premium Member

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    Just the other day my truck decided to act up. If i drove like a grandma the truck would run fine and everything. i run 35's and 3.08's so L is a must. sm465 trans. if i let the clutch out,,, floor it in L, its fine, shift floor it in 1st its fine,,, shift into 2nd floor it and pretty soon its starts surging, the tack flutters like crazy, then goes to 0, i let off and get a nice backfire. To me it seems like its starved for fuel. it only does this under load... I thought clogged fuel filter so i changed it but that didnt help a single bit. What do you all have for suggestions? I got a date saturday and really need to resolve this issue :D Thanks for the help

    Cole
     
  2. MTChevy

    MTChevy 3/4 ton status Premium Member

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    I've been searching on this... im thinking it has to be carb issue... maybe
     
  3. Cricket

    Cricket 3/4 ton status

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    What kind of carb?

    What's your fiuel pressure look like?
     
  4. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    Don't rule out an ignition problem.

    When you say you've been searching do you mean just here or the entire internet?

    Reason I ask is because there are other places with more carb info. Check out www.thirdgen.org, it's really helped me out with my carb issues. Or any other tuning issues.
     
  5. MTChevy

    MTChevy 3/4 ton status Premium Member

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    ive just been searching on here... its just the 4bbl Q-jet... I kind of thought it could be a ignition problem? due to the tach fluttering like it does... Fuel pressure is good.
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    I'd vote for weak ignition coil,or pick up coil in the HEI distributor..or the module not advancing the dwell as it should possibly..any low voltage ,or shorts in the HEI main power wire will affect spark intensity under load too..

    The 'fluttering" tach kinda says to me its electrical in nature,that and the fact changing the fuel filter didn't improve things any..did you check the fuel PUMP too??..pressure and volume OK??...:confused:
     
  7. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    If it's been awhile since the plugs and what not have been done, I would start with replacing the plugs, wires, cap, coil, and rotor.

    IMO those are easy things to do and it doesn't hurt anything but the wallet to do it.

    I remember my old '64 pickup just started running poorly one day. Not anything like your problem, but it wasn't running good. I replace the plugs and that did it. They had gotten badly fouled.
     
  8. theperfectgarage

    theperfectgarage 1/2 ton status

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    I'm leaning twords ignition just because you mentioned the tach going crazy at the same time. Make sure your ing. is getting good juice.
     
  9. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    Ignition also, under load is when they first act up.
     
  10. MTChevy

    MTChevy 3/4 ton status Premium Member

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    Thanks for the replies guys... I think I'll slowly replace dizzy parts next. check voltage, and maybe fuel pressure once more. plugs and wires are almost brand new.
     
  11. MTChevy

    MTChevy 3/4 ton status Premium Member

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    Turned out to be pickup coil and module...
     

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