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Thread: trouble tuning VE table and sprak

  1. #1
    Tuner in Training LM7S104X4's Avatar
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    trouble tuning VE table and sprak

    Hi everyone, im looking for a little guidance of what i seem to be doing wrong. I have read countless post and watched tons of tuning instructional vids trying to learn how to do this correctly but i seem to be having issues tuning the VE and spark tables from the histogram off the scanner.
    No matter what i do it rarley stays on point and always seems to be changing. Ive switched to SD only and have been using RTT to try and narrow it down but the graph is
    looking pretty wacky, closed loop and long term trims are disabled. can you guy help me out a little i would greatly appreciate the advice. I live at high elevation in Colorado (6k-10k) if that has anything to do with the odd looking table.
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  2. #2
    Tuning Addict 5FDP's Avatar
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    The MAF dtc's need to be set to MIL on first error to drop into speed density straight away.

    You left the short term fuel trims active, so if you are using a wideband to calibrate the VE table, all your data is skewed.

    Your open loop EQ ratio isn't right. You must commanded stoich at all times outside of PE. You must set the open loop eq ratio to 1.00 for all cells above 130-140 degree.

    I don't know what your spark issue is other than seeing some knock retard in the log. The speed density OS retains the stock OS timing functions where the high/low octane tables do not need to be the same. The low octane table can/should have less timing it in for when there is knock. Your current timing is probably too high and the fueling isn't right yet, so knock can happen. I'd lower the timing to 24-25 degrees and work on the airflow model more. Pick a steady commanded AFR to run for power enrichment an make it match that using the wideband.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
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    TRY THIS FOR MAIN VE.png

    try tis for main VE
    2003 5.3 4x4

    hope this came thru

  4. #4
    Tuner in Training LM7S104X4's Avatar
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    5FDP, even if i have switch the os to speed density enhanced? i must have over looked it and left the short terms active thank you for pointing that out! i am using a aem wideband to tune with and will correct my open loop EQ. i went back to stock timing until i can get the VE table figured out.

  5. #5
    Tuning Addict 5FDP's Avatar
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    Yeah, the speed density OS is just an "add on" on top of the factory OS, you don't lose any of the previous functions.

    It's when you do a speed density only tune on the stock OS will it revert to the low octane timing curve because the MAF is failed.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  6. #6
    Tuner in Training LM7S104X4's Avatar
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    oh man thank you for the tip. truck is running so much better......VE table is getting way better but still looks pretty wacky, its getting close to stoich.
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  7. #7
    Tuning Addict 5FDP's Avatar
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    Smooth the table after each change. Using both the functions within the editor and doing it by hand. Get rid of the spike in the middle and smooth the rest out.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.