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Thread: Does a drive-by-wire car utilize the idle spark tables?

  1. #1
    Tuner
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    Does a drive-by-wire car utilize the idle spark tables?

    I noticed in the tune file for my 98 Vette that the TPS percentage for the main spark tables is 1.2%. If I am correct that means that below 1.2% TPS the idle spark tables are used and above that the main spark tables are used. Thing is the car has an electronic throttle body and is around 15% at idle so is it just not using those idle spark tables?
    98 Corvette Coupe - Texas-Speed 408ci iron block, PRC 237cc heads, Ed Curtis Cam 239-247-115 .624-.624

  2. #2
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    ???
    98 Corvette Coupe - Texas-Speed 408ci iron block, PRC 237cc heads, Ed Curtis Cam 239-247-115 .624-.624

  3. #3
    I am just guessing but there is a PID for the throttle pedal position (which would be zero at idle) and also for the TPS itself, and I would guess that the <1.2% applies to the pedal position, not the throttle blade.

  4. #4
    Advanced Tuner VodeAn's Avatar
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    Jun 2012
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    One of my personal vehicles is DBW and it still uses the idle spark tables.

    Their's a really easy way to verify yourself, set your main spark high and low octane tables to a certain value during idle, (for instance, make everything below 1200rpm 28 degrees) and make your idle spark tables something else (say 18 degrees), zero out or reduce any modifiers tables. Flash cal only and save as a new file.

    It might run like poorly or only for a few moments, but you'll be able to see what table is being used by the value in the scanner. Shouldn't take more than 5 minutes to try.

    Flash back to what you had before after you're done.