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Thread: e38 unexplained timing spikes while working on vve

  1. #21
    Advanced Tuner
    Join Date
    Aug 2021
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    835
    What is your thread called? I want to check it out to see if thats what i have going on. Ive logged misfire on every cylinder and didnt pick up any even during a wot pull.

  2. #22
    Advanced Tuner
    Join Date
    Apr 2016
    Posts
    331
    Not sure which thread you are asking about? The AC torque reduction will just be a sudden drop in timing when the ac clutch comes on, not a misfire. If set too aggressively (pulling too much timing), it will create a noticeable "fishbite" feel.

  3. #23

  4. #24
    Advanced Tuner
    Join Date
    Aug 2021
    Posts
    835
    appreciate the link! I'm going to check it out and see if that may be my issue as well or if it's just that I can't tune VVE.

  5. #25
    Tuning Addict
    Join Date
    Jan 2015
    Location
    Franklin, NC / Gainesville, Ga
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    6,781
    Could I get someone having this problem to either email or pm me please that wouldn't mind doing a quick test. Ran into this same problem on a genv and would like to test a theory as it seems to have fixed it. Funny thing was that it was only doing it to that one in blended mode whereas gen 4's do it only in sd mode. Never the less - dynamic air would shoot through the roof, fuel dump was occurring and timing being yanked causing bucking....

    Thank you.
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  6. #26
    Tuning Addict
    Join Date
    Jan 2015
    Location
    Franklin, NC / Gainesville, Ga
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    6,781
    OK, so on the Vgen it wound up being the prediction coefficients being zeroed out that caused this issue. It was causing the dynamic airflow logic to go bonkers and freeze up the coding in the ecu for brief moments at a time... So, doesn't seem to be the issue on the 4th gens, but something to keep in mind if your having this issue and you've altered them or something related to dynamic airflow...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC