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Thread: Throttle closing on downshift

  1. 08-22-2017 #1
    cfry
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    Throttle closing on downshift

    Hello guys.
    Here is my platform:
    2010 Camaro A6 with LS3 conversion. BTR Stage 2 and a 3200 Stall. 3.73 gears.

    I am working on my tune, and have developed a hiccup on a 6-3 or 6-2 downshift. My 12.7AFR log file with wideband is rather large. Here is the time hack for the event: 6'24.571". This log was not with the latest tune, just the most recent with my wideband on it. If you watch AFR right before the event, I am commanding .868 lambda. However, there is roughly a .3 second time where AFR continues to climb until it hits13.5-.6. That is when throttle slams shut and I get a nasty backfire. Then the car takes off. Since then, I put it up on a dyno and adjusted VE tables and some fueling issues. Also added a degree of timing at WOT since the log was taken. Initially thinking it may be a onset volume issue (had a zl1 pump laying around) I put a pump in it. Obviously I am missing something. Wondering if this could be a DFCO issue, or if I sped up my shifts would it help. The fuel pump log has an event with the latest tune, just not with my wideband. The time hack for that is 3'33.528". If you need any more info please let me know. Thanks for the help in advance.
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  2. 08-22-2017 #2
    cfry
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    Attached a smaller file of the event.Throttle close.hpl
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  3. 08-22-2017 #3
    5FDP
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    Can you log what torque mngt is taking place, I saw it yank 45 degrees out for TM and that is when it happens. It may help with solving the problem. Kinda odd to see that happen.

    Other random tid bits, you may want to disabled desoot mode as well as disable burst knock. I see burst knock yanking a lot of your timing in log too.
    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.
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  4. 08-23-2017 #4
    cfry
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    trans torque ect.hplHere is an example with type of torque management. Both are in the Trans. I also pulled my max burst down to 4 degrees.
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  5. 08-24-2017 #5
    cfry
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    Anyone have any thoughts?
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  6. 08-25-2017 #6
    SSUte01
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    The ETC will close to control shift flare if spark torque management alone can't control the downshift. You can disable it, if that is actually the case here (can't view currently) but it can be indicative of the trans not being up to the task mechanically for the downshift. This may or may not be applicable to your case
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  7. 08-25-2017 #7
    cfry
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    I'm not sure I understand what you mean by it cannot mechanically handle the downshift. Could you elaborate?
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  8. 09-07-2017 #8
    Tre-Cool
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    Your shits gonna break/burn out clutches because it can't pull enough power or perform the shift quick enough for what's being asked....
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