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Thread: idle ignition timing and return to idle issue

  1. #1
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    idle ignition timing and return to idle issue

    Looking for help tuning idle on a 5.7 block, trick flow genX 215 heads and cam, Nick Williams DBW throttle body and LSXRT 102m intake with Fast 33lb/hr injectors. Truck starts and takes throttle very well on current tune. I have not started tuning for driving or WOT. Motor used to have truck heads, mild cam and small ls1 intake / TB. Cold and hot starts fine. During idle the timing jumps all over from 7 to 27 degrees and fuel AFR is all over, but usually stays about 15.4 (command is 14.3) The ECU is from a 2000 silverado. I increased the airflow at idle and increased idle RPM to 800 but that is about it. When you blip the throttle it will fall below 800 and dies about every other time. I have included 2 idle scans and the tune. Any help would be appreciated. I think i'm missing something simple but being new means I need some help. Thank you.
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  2. #2
    Tuning Addict 5FDP's Avatar
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    Don't get too crazy with idle corrections if you have yet to even correct the overall airflow model. You don't want to change a ton of idle airflow and timing settings if the all the fueling is still way off. Your trims show it's rather lean so address that first with the MAF/VE then work on the idle stuff.
    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
    Advanced Tuner KFXGUY's Avatar
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    Quote Originally Posted by JOettel325 View Post
    Looking for help tuning idle on a 5.7 block, trick flow genX 215 heads and cam, Nick Williams DBW throttle body and LSXRT 102m intake with Fast 33lb/hr injectors. Truck starts and takes throttle very well on current tune. I have not started tuning for driving or WOT. Motor used to have truck heads, mild cam and small ls1 intake / TB. Cold and hot starts fine. During idle the timing jumps all over from 7 to 27 degrees and fuel AFR is all over, but usually stays about 15.4 (command is 14.3) The ECU is from a 2000 silverado. I increased the airflow at idle and increased idle RPM to 800 but that is about it. When you blip the throttle it will fall below 800 and dies about every other time. I have included 2 idle scans and the tune. Any help would be appreciated. I think i'm missing something simple but being new means I need some help. Thank you.

    You're using a DBW throttle body with a drive by cable computer?


    Your VE table needs to be tuned. If its not, it will not idle properly. thats why your fueling is erratic.
    2004 5.7 gto
    7875 turbo
    Heads/cam

  4. #4
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    Quote Originally Posted by KFXGUY View Post
    You're using a DBW throttle body with a drive by cable computer?


    Your VE table needs to be tuned. If its not, it will not idle properly. thats why your fueling is erratic.

    Good catch. I did not mean to write DBW, should have been DBC. thanks

  5. #5
    Advanced Tuner KFXGUY's Avatar
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    one more thing. put your timing tables back to stock. add about 5 degrees to the whole table. test. if it fixes it, fix your timing in the cruise and wot regions to what you want and leave the idle area alone. you could blend the idle area a little more, you go to far and youll get idle hanging or dipping.
    2004 5.7 gto
    7875 turbo
    Heads/cam