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TBI bog'n out when I slam throttle

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by GREASEMONKEY, May 11, 2003.

  1. GREASEMONKEY

    GREASEMONKEY Registered Member

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    TBI bog\'n out when I slam throttle

    I've never had this happen on a fuel injected engine before but recently i've added shorty headers, flowmaster muffler (new cat and O2 sensor) and a K&N filter. Anyway when I mash the throttle i'll get a big hessitation then it'll take off. Kind of like when I use to have a poorly adjusted 4 brl carb. hard to describe but kind of like "bbbbbbbbbbbbbbbbbbwwaahhhhhhhhhh". know what I mean? /forums/images/graemlins/confused.gif 88 350 w/tbi auto trans.
     
  2. DukeBoy88

    DukeBoy88 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    I had this problem before, however it went away on its own. I did notice it only happened until the engine warmed up. I kept thinking it was tied into the MAP or TPS, but It fixed itself without me doing anything at that time. Do you have any codes? sorry I can't be of more help.
     
  3. gmule

    gmule 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    How's your timing? there could be enough slop in the chain to notice
     
  4. Thunder

    Thunder 3/4 ton status

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    Re: TBI bog\'n out when I slam throttle

    First of all check for trouble codes to make sure the TPS isn't bad.
    How's the fuel filter? If its over a year old change it.
    Check the timing
    If that doesn't cure the problem you may need one of these
    casperelectronics.com scroll down page till you see 88-93 GM Throttle Enhancer.

    You may also need an adjustable fuel pressure regulator.(requires some disassembly of the TB. They help to take the flat spots out of your acceleration.
    If you want to do a little grinding on the TB you can also boost fuel pressures to over 15 lbs with these little goodies.
    Go here:turbocity.com
    I have used or am using all the stuff on that page. It all works good to improve TB performance.
    Now that you have upgraded your exhaust its a good time to start improving your Throttle Body.
     
  5. dheavychevy38

    dheavychevy38 1/2 ton status Premium Member

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    Re: TBI bog\'n out when I slam throttle

    I HAD THIS PROBLEM WITH A 1994 SUB WITH TBI IT WAS THE INTAKE GASKET MAN WAS THAT HARD TO DIAG. GOOD LUCK
     
  6. 87sm465np208

    87sm465np208 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    hows your fuel filter, my friends did somthing similer to this and it was the fuel filter.
     
  7. GREASEMONKEY

    GREASEMONKEY Registered Member

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    Re: TBI bog\'n out when I slam throttle

    thanks for all the tips. Yeah, i'm going to change the fuel filter, i've never done it and it's hard telling if it's ever been done. It could also be the intake as mentioned above. Could be the mechanics that put on the replacement jasper head didn't torque it right. Cheers all
     
  8. Itali83

    Itali83 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    Does it do it all the time or just when cold?? does it start hard, if so your coolant sensor may be mad. Mine was hard to start and would fall on it's face when cold but ran ok when warm with the bad coolant sensor. Just another thing to think about.
    Ben 87 Jimmy + 89 Blazer
    /forums/images/graemlins/usaflag.gif
     
  9. MousePowrd

    MousePowrd 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    All these suggestions are great, but you are overlooking something simple. For this to happen immediately after the header install, make sure you didnt knock a wire off, make sure the o2 sensor is grounded (not too much anti seize on the threads) and check all vacuum connections. This is the exact symptom of a vacuum line being knocked off.

    Finally did you disconnect your battery to clear the ECM? You have to clear the computer any time you make a significant change like headers
     
  10. GREASEMONKEY

    GREASEMONKEY Registered Member

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    Re: TBI bog\'n out when I slam throttle

    it runs smooth as can be and behaves really nice under normal driving conditions. I noticed it the other day when I stomped on it. It just kinda did nothing, like it stalled and then took off. I paid a lot of attention to wires, lins and truly believe everything is hooked up. Yes the neg. cable was off and reset the CPU. Also set the timing per manual. I remember when I had my old CJ-8 which had a bad fuel filter at a certain speed it would cough and sputter. After the initial hesitation it runs great. I really haven't been able to run it for a extended period as i'm waiting on my new plates from DMV. really can't go far from home in fear of police. Big red trucks are not inconspicuous.
     
  11. MousePowrd

    MousePowrd 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    If it runs good at WOT you can rule out fueling problems. I would look more into vacuum leaks. Look for a split hose, leaking manifold, cruise control lines, charcoal lines, etc.
    To check for a leaking manifold just spray WD40 around the base of the manifold and see if the idle changes in the engine. If it does there is a leak. Also spray around the base of the throttle body as the gasket can leak also
     
  12. fortcollinsram

    fortcollinsram 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    I second the vacuum leak...My 350 TBI was running like monkey turd I replaced sesoners, the EGR rebuilt the TB..no luck..well I am swapping in my 454 next week and when I was pulling stuff off my 350 to get ready to yank it, I found a nice split on the vacuum line that goes from the TB to the MAP sensor...So get some starting fluid and start shooting lines and see if the engine speed up when you hit vacuum lines and such...

    Chris
     
  13. MOTORHEAD

    MOTORHEAD Registered Member

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    Re: TBI bog\'n out when I slam throttle

    I feel like such a idiot /forums/images/graemlins/angryfire.gif (i'm greasemonkey on my home comp). It's amazing what a little gas will do. Seems my problem was that I was empty. Yes, bought a new fuel filter put that in, ran it around the block same damn problem. Looked at the needle and i'll be damned if it wasn't on E. Imagine that, a truck running like crap because it's on fumes. Amazing what a little gas will do.
     
  14. daleearnhardt01

    daleearnhardt01 1/2 ton status

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    Re: TBI bog\'n out when I slam throttle

    Same thing happened me yesterday. I was doing a Uturn and was gonna get on it so I came round the turn fast and when I stomped the gas she died. Haha, I definetely needed gas.
     
  15. Thunder

    Thunder 3/4 ton status

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    Re: TBI bog\'n out when I slam throttle

    Yes it is. Last night I had a little gas. I cleared everyone out of the whole house /forums/images/graemlins/rotfl.gif
    Glad you got it fixed and it was simple /forums/images/graemlins/thumb.gif
     
  16. Greenie

    Greenie Registered Member

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    Re: TBI bog\'n out when I slam throttle

    change the fuel filter. Disconnect the battery to reset the ecm. Are you injectors clean? Try some injector cleaner.
     

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