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  1. #1

    Default 89 TBI 454 won't idle

    3500 truck, 207000 miles, supposed to have been rebuilt.

    I replaced plug wires, plugs, unhooked "brown wire" connector under glovebox and held throttle with a clamp (to keep it running) to adjust timing to "0", plugged brown wire back up, still won't idle.

    Cleaned IAC, checked vacuum hoses, there is a device about the size of a half pack cigarettes with a plug and wires on one end and a vac hose attached to intake on other,its loose under air cleaner, is this the MAP sensor? Could this be the problem? Cound the TBI need rebuild? Spray pattrern looks good.

    Now the check engine light is on, I don't have a OBD 1 scanner, is there a jumper/count flashes method to determine the code?


  2. #2


    You need to jump the ALDL at pins B and A.
    Attached Thumbnails Attached Thumbnails aldl4dn5.jpg  

    2004 SILVERADO 2500HD LS
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    285-75-16 Cooper ST All Terrains
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    Linux Bed Liner
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    Other rides:

    1967 Landcruiser <350 Chevy>
    1970 Camaro
    1990 Geo Metro Convertible
    2007 FJ Cruiser

  3. #3


    No code, followed procedure to reset IAC. Got it to idle at 450rpm, shut it down, plugged IAC back in, now it won't idle and will barely start.

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