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  1. #1
    Fuel Injected!
    Join Date
    Jan 2015
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    111

    Tuning startup on $EE

    1995 LT1 M6 firebird formula

    it’s really anemic during cranking/startup it kinda hesitates. Every other lt1 car I’ve had starts up healthy.

    what tables can I tweak to try make this better?

  2. #2
    Fuel Injected!
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    Mar 2013
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    Post a list of modifications if any.

  3. #3
    Fuel Injected!
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    Jan 2015
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    Car is pretty much bone stock to my knowledge. I noticed that it has an airfoil. I've installed full length headers and egr block offs.

    I've made some tuning changes here is a summary :

    Disabled egr & air pump
    Turned down idle spark correction
    Bumped idle timing 4*
    O2 int delay increased
    O2 swing voltage bumped up
    Cat protection disabled
    Changed blm cell boundaries
    Disabled stall saver

    Its definitely flowing more air based off maf readings I'm currently working on getting those tables right along, with the ve table

  4. #4
    Fuel Injected!
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    Mar 2013
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    None of these should affect startups. It will be either weak spark, too much or too less fuel, or not good enough opti spark signals to pcm.

    Is it making long cranks with no signs of starting, or is it trying to start during crank but can`t engage all cylinders in a timely manner.


    If you are having delay in high res signal the pcm will dump fuel only when it gets the signal or an error is set.

    Revise the ignition system.

    Check fuel pressure during cranking.

    Check opti signal.

  5. #5
    Fuel Injected!
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    the problem isnt long cranking times. it fires right up everytime as soon as you hit the key no problem.

    my issue is that when it does fire up the first time it struggles like a slight hesitation in that initial startup but it idles fine. its always done this even before i changed anything on the bin. I was just hoping theres some tables that i could tweak to alleviate and sort of bandaid this issue.

    overall the car runs great. my blms are great from the couple of logs ive taken so i dont suspect theres a vaccuum leak.

    a hardware issue was my first thought but im not sure what it could be. distrbutor cap is brand new. fuel filter and fuel pump are brand new. injectors were swapped from a known running engine (the ones on the car were locked up).

    I guess it could be an injector issue.

  6. #6
    Fuel Injected!
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    Sep 2012
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    Replace the ignition coil. Every LT1 I've had with a weak startup has had a failing ignition coil. In fact, you ought to consider replacing the coil and ICM just as maintenance. They both wear out.

    You could always try putting a stock tune back in the car...

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