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Thread: TCC unlock problem after intake manifold swap

  1. #1
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    Default TCC unlock problem after intake manifold swap - Resolved

    To make the story short, the reason for my tcc not staying locked was a misadjusted cruise control brake switch that by the way inhibited cruise control function as well. I never noticed the cruise not working since i was doing all testing in city.


    Hi all,
    I have a 2000 Corvette and went from a LS6 78mm intake to a Fast 102 with 90mm TB (LS2).
    After that change I noticed that 4th gear TCC operation was different than before. Now the TCC unlock at any speed as soon as I get below 14% throttle opening. I also had 3rd gear TCC enabled but now have a hard time to get it to work at all.
    The only things that I changed from the old to the new tune were B4349 ETC Throttle Area conversion from .255 to .320 and of course the VE table .
    Going back to the old values on B4349 didn't change the new behaviour.
    I have an old log in which my car stayed locked with no throttle incl. DFCO and now a new log in which it unlocks anytime I get below 14% TP.
    The base tune (COS5) was not changed.
    Do you have any ideas on how to get the old behavior back since the constant unlocking and locking is really annoying.
    I'll attach the logs and my current tune to see what I mean.
    Thanks
    Alex
    Alex_baseline COS5 rebuilt trans w_3rd TCC_0315.tun
    Log_0174_transmission test.efi
    Log_0192.efi
    Last edited by Alex99; July 28th, 2013 at 12:36 AM.

  2. #2
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    After re-checking the forum archive I ran across this thread
    http://forum.efilive.com/showthread....nlock-Problems
    Its very similar in term of the problem but even disabling the misfire detection (C5601 set to 1), won't bring back the correct TCC lock behaviour.
    BTW, i run a 2800rpm Vigilante stall.
    Do you think thatdoing a full reflash with an older tune that used to work might help?
    Thanks
    Alex

  3. #3
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    A full reflash won't help. You need to raise the misfire counts to stop the random unlocking/locking. Some will simply enter the max value for the entire table; but that will effectively disable misfire detection which you still need. 3rd gear TC locking is tough even on a small converter like that; and honestly not really needed for anything other than a stock converter. You should also look at raising the TC lock up mph as well as the 3>4 shifts.

  4. #4
    Joe (Moderator) joecar's Avatar
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    Also, there are several TSTATE pids which show the reason for TCC unlock, check these to see if misfire is the reason (it very most likely is)...

    Also, note that changing converter means the rotating mass/inertia has changed and a CASE relearn would be a benefit.

  5. #5
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    Those are some good tips, I'll try them out and will report back.
    Thanks Alex

  6. #6
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    Quick feedback on the suggested actions. I maxed out the misfire tables and logged with the TSTATE pids to see whats going on. TSTATE 09 and 10 are the interesting ones that show the possible reasons for unlock. Unfortunatey, no luck in the misfire section although i was intentionally creating unlocks.
    Then i tried to do a CASE relearn and wasn't able to. I checked all the instructions but somehow i don't get e response from the software once i hit the button to start the procedure. Even after just trying to rev to 4500 i don't get the miss that needs to come. I've done it sucessfully in the past with the older version but this time no luck. Ill try again tomorrow.

  7. #7
    Joe (Moderator) joecar's Avatar
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    Did you have the brake applied...?

  8. #8
    Joe (Moderator) joecar's Avatar
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    Hmmm, re-reading post #1, you went from an LS6 intake to a FAST102 (with throttle body swap) and now your TCC unlocks when TP goes below 14%...

    try setting D1001-D1009 to stock 2002 F-car values.

  9. #9
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    Hi guys,
    yesterday I changed D1001-1009 to the 2002 F body values - no change in behavior.
    Today I was able to do a successful CASE relearn but also didn't notice any change in unlock behavior.
    Its unlocking so early, I'm still in the process of lifting my foot from the gas pedal and its unlocked already, its really annoying.
    Please see my tune, currently misfires are disabled, unlock speeds etc. are stock F-body and CASE relearn was performed.
    I'm not sure what other influence can be responsible for this since it worked before.
    I also reset the ETC tables (primary/secondary) to values that used to work before.
    I'll attach my last tune, FYI.
    Thanks
    Alex

    Alex_baseline COS5 rebuilt trans w_3rd TCC_0319.tun

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