Those of you with TBI, does your ignition module control timing?

Discussion in '40- & 55-Series Tech' started by badass, Feb 16, 2009.

  1. badass

    badass

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    Hey fellas, i was just wondering for those of you with the tbi conversion on your 2f, how many of you have the tan/black wire hooked up. It's the one that controls timing functions.

    I would love to keep it hooked up because when it is i have much more power, throttle response, and better mpgs... but when it is connected engine does not idle. So what gives?? Do i HAVE to have an aftermarket dizzy?

    This is a stock 2f with the stock modified toyota dizzy and the 4.3 chevy tbi. Any advice is appreciated.
     
  2. Sputnik40

    Sputnik40

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    I'm pretty ignorant on my setup - but I do know that I remove the brown wire to set my base timing and then reconnect. Did you set your timing this way? Given no smog - higher performance and other variables - did you get radical enough on the base timing to allow sufficient advance once it's reconnected? Has been so many years since I've even had to mess with mine that I can't remember - but think I set it in mid teens. Runs like a raped ape.

    I could never read that long epic of a thread you had on this - thought it was all resolved and running fine?

    You're better off trying to get Marshall to help you...
     
  3. Trollhole

    Trollhole THC Supporting Vendor Moderator

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    Until you get a Data cable and can read what the computer is doing you will never resolve your issue by connecting or disconnecting wires.

    The computer is what is causing the idle issue. Until you can see what it is seeing you are just throwing darts.

    I believe we have discussed this before but you have fixed the counter weights in the bottom of the dizzy so they don't move, correct?
     
  4. badass

    badass

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    yes i have removed all weights and vaccum advance and welded it up. I do not have a data cable, but i'm just trying to figure out what would cause the truck to not idle when the tan/black wire is hooked up.

    Everything works fine when it is disconnected.
     
  5. Elbert

    Elbert SILVER Star

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    on the GM TBI.... with "control wire" unplugged you are in (Base timing) or in other words the ECM is not controlling the timing. When the wire is connected, the ECM is in control of the timing. I assume you are using a GM ECM? I'm no expert, but did have a 92K1500 with TBI 350.

    I do know the ECM has to inteface with the distributor correctly and base timing has to be exact. On the 5.7 GM engine base timing is 0 degrees, a little more or less and you have problems.

    Assume you have an ALDL connector in which to check for trouble codes?
     
  6. Downey

    Downey

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    The ignition module works with the 2 pulse VSS to control idle functions. Idle functions are everything that happens below 2 mph. This includes fuel enrichment upon starting, automatic choke actually working, engine not dying every time you come to a stop, bla, bla, bla. Vehicle has no drivability without these things intact and working. They also allow the ECU to control timing functions once all timing is neutralized in dizzy.
     
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