"Bucking" with '86 318 lean-burn

Discussion in 'General Motoring' started by r_s_bogar, Jun 7, 2005.

  1. r_s_bogar

    r_s_bogar Guest

    I have a 1986 Gran Fury with 5.2L/2BBL and "Lean Burn" feedback
    carb. Occasionally, when cruising at higher speed, (typically around 75
    MPH, but can happen as low as 45) when throttle goes from just above
    idle to a little farther open, does several seconds of severe
    "bucking" or surging. Troubleshooting has been: replacing carb with
    non-feedback type didn't help. Blocking off EGA vacuum didn't help.
    Swapping out computer unit reduced frequency of occurrence, but
    didn't stop problem entirely. Disconnecting and plugging vacuum to
    computer stops problem, but causes loss of power and open-loop, gas
    wasting carburetor operation. Vehicle needs to keep lean-burn stuff on
    to pass MD emission inspection. Engine otherwise runs well, passes
    inspection with 1/10 allowable emissions. Alldata doesn't show any
    TBs for this.
    Has anyone else seen this sort of problem, or have any suggestion?
     
    r_s_bogar, Jun 7, 2005
    #1
  2. r_s_bogar

    calcerise Guest

    Wow. No one else runs lean burn anymore! Secretly plugging the vacuum
    line and reworking the carb to run conventionally might fix problem. Or
    perhaps you could fit EFI and a catalyst in your state, since there is
    no more leaded gas anyway. Finally, you could convert to LPG...
     
    calcerise, Jun 20, 2005
    #2
  3. And leaded gas has exactly what to do with an '86 *anything*, pray tell?
     
    Daniel J. Stern, Jun 20, 2005
    #3
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