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Thread: TBI Injectors

  1. #1

    Default TBI Injectors

    Hope someone can help me here. My 88 3500 started running rough and stalling out at idle after a long ride today. Its TBI and the pasenger side injector is spraying alot more fuel than the driver. Pulled the injector out and the injector filter looked ok, a bit brown. Should bouth injectors spray the same amount of fule or is the pasenger the main and driver side the secondary.

    Any help would be GREAT. Thanks
    89' 3500 caddy seats, mesh & mat black grill, rollpan, and ALWAYS partly disassembled. 91 350 trans am 5-speed (oops wrong forum).

  2. #2

    Davandy's Avatar
    Join Date
    Jun 2005
    Haasdonk Belgium


    Welcome to the site I think it should be the same amount of fuel both sides
    Peter Smet
    Haasdonk, Belgium

  3. #3


    I havent looked at the book on that engine in a while so I dont know the exact range but all the injectors should be within a few lbs of each other.

  4. #4


    thanks, I replace the bad injector. aparently they should bouth spray the same amount of fuel just timed difrently. The truck will idle now but still runs rough im wondering if i fowled some plugs running with the bad injector. I will pull them this weekend and check.

  5. #5


    Changed the plugs, Still VERY rough, any one have any idias so far there is a new injector, plugs wires and semi new distributor. I might try fuel filter next. Checked all vacum lines thay all seam to be right. any help would be great this trial and error trouble shooting is geting expensive.

  6. #6

    Davandy's Avatar
    Join Date
    Jun 2005
    Haasdonk Belgium


    You should try the fuel filter first that's what I would do.
    You can check for vacuum leaks with break cleaner but be careful whit that.

  7. #7

    Default Still an issue

    Cant get thr truck to run right still. so far i have checked for vacume leaks, checked timing, changed all plugs and cap, changed fuel filter, pulled the codes, they said i had a bad map sensor and replaced the map sensor. next step is to light the truck on fire.

    It idles like its running on 5 cylenders, seams ok at speed but not great. any help would be awesome.

  8. #8


    Your coil could be weak. I know our trucks are different years but I have had to replace two coiul pacs for the same reason. I think I would try that.
    Chris S. The GoFastPadre I like to drive fast and I've got the speeding tickets to prove it. 00 Sierra Z71 ECSB K&N CAI Pacesetter Shorties (soon to be replaced with LT's) Magnaflow HFC's Flowmasters with True Duals and H-Pipe more mods to come

  9. #9


    you neglected to state the miles on your vehicle. being an 88 ,i wouldve started with a compression ck first. once i knew the engine was tite {no big variance in comp. between cyls.}id look for ignition problems moisture in dist. cap wire arcing etc.

  10. #10


    If it does act like it is idleing on 5 cylinders you could try pulling the plug wires off wile it is running, once you find the cylinders that are not firing that should help to narrow down what is going on, but be carefull pulling plug wires, I would use a pair of insulated plyers.

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