Page 1 of 2 12 LastLast
Results 1 to 20 of 21

Thread: 6L80e Interesting TM issue on power downshift

  1. #1
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905

    6L80e Interesting TM issue on power downshift

    The car is an 09 G8GT with LT's,CAI and a Yank 3200.
    I can be going say in 6th gear, punch her, the trans would donwshift to 2nd, then there is pause in acceleration, then off she goes at full throttle in 2nd gear. initially i thought i had my powerdownshift's set to quickly, and the trans was adapting pressures or whatever to my new verter (had it installed last week), yesterday for shit and giggles, i took a couple of logs when this event was happening, and to my surprise, she's is closing the throttle down right when i see the trans shift into 2nd. I logged etc source, etc tgmgt type and torque mgtm advance.

    when i go WOT, etc tqmgt type is "none", etc source is "maxpos"
    When the throttle closes, etc tqmgt type goes to "trans", and etc source goes to "idle"
    then the throttle opens up again, and off she goes.

    How can i fix this little issue ? i have set the spark min tgmgt to be 2*, this have worked in the past for the hesitation on power downshifts, i just didn't notice the throttle closing like this before, this of course slows down the car in the moment where you most need it under special circumstances , this doesn't seem to happen when the trans has to downshift 1 gear down, example from 4-3 or 5-4, at least doesn't feel like the pcm is closing the throttle, i don't have a log for that one though. my TM master switches are stock, i want TM, not just like this much.

    Attached you'll find a couple of logs and the config file i have.

    Thanks.
    Last edited by bluegoat06; 10-16-2012 at 04:27 PM.

  2. #2
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    This is mt TB closing with this trans tqmgt


    Uploaded with ImageShack.us

  3. #3
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    Chris@HPT, could you please let me know what's the meaning behind ect tqmgt type ="trans" with ect source ="idle" ?

    I tried a tune with the power downshift master switch only set to disabled, still did this.
    Then tried another one with the neutral down skip master switch disable only, same behavior. i didn't save the power downshift disable log, but it did exactly the same. also tried modifying the TM adders to remove almost all TM, same thing, also tried adding 8* to the min spark tgmgt, same thing.

    What else can be causing this ?



    Thanks
    Last edited by bluegoat06; 09-27-2012 at 07:34 PM.

  4. #4
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    Well, after messing with the master switches and disabling TM for neutral skip downshift,power downshift TM and all almost every TM master switch to disable, i decided to put all those back to enable,just like i had them, and play with the other switches, tip-in tgmgt, flare tgmgt and limit tgmtg, i can't believe it, but i set all those back to stock, except the tip-in tgmgt upshift and flare tgmgt upshift, and now she's shifting perfect. dear lord she's shifting great
    Last edited by bluegoat06; 09-28-2012 at 12:10 AM.

  5. #5
    Tuner in Training
    Join Date
    Aug 2012
    Location
    Columbia, SC
    Posts
    22
    Would love to see where you ended up..still trying to dial in my transmission and I have downshifting issues.

  6. #6
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    Post your tune, and lets take a look, is this a tune for a G8 ?, what mods do you have ? I have pretty much all TM switches enabled from the factory, no problems with flares or trans shifting issues. i have very little TM on the upshifts about 10-12% at WOT instead of 0%TM, i always advocate using some TM is beneficial for the trans , i make use of the TM adders though to remove TM from the shifts, but my master TM switches are mostly stock.
    Last edited by bluegoat06; 10-16-2012 at 04:26 PM.

  7. #7
    Advanced Tuner
    Join Date
    Jun 2009
    Posts
    202
    I have to piggy back...TM is a must if you want cleaner shifts and trans longevity. So many guys are quick to just turn it off
    11.49 @ 118 1.49 60' Bolt on 2010 IOM Camaro

    www.6l80etuning.com 6L80/90 Tuning

  8. #8
    Tuner in Training Mark Wheeler's Avatar
    Join Date
    Mar 2011
    Posts
    14
    Bluegoat, I've been fighting similar behavior in my downshifts. After playing with everything I could think of nothing made it better. In my case it seemed to go away when VE is enabled. So I was wondering if it has anything to do with our MAF only tunes. I haven't completely tuned the virtual ve just yet so I need to do more work and testing.
    2009 hot white G8GT - Vararam, HSRK, street tuned, Kooks longtube headers and x-pipe. 12.675 @ 112.05mph.

  9. #9
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    I run mine MAF only, and the issue was gone after i set some of those TM settings back to stock. Do you have the issue on power downshifts as well ?
    Do you have a log to see if it's the same thing i was seeing in my logs ?

  10. #10
    Tuner
    Join Date
    Jul 2011
    Location
    Fort worth, TX
    Posts
    126
    I had this issue and for me it was all in the torque management on the downshifts, set that to enable and boom she down shifts like a champ.
    15 C7Z M7

  11. #11
    Tuner in Training Mark Wheeler's Avatar
    Join Date
    Mar 2011
    Posts
    14
    Quote Originally Posted by bluegoat06 View Post
    I run mine MAF only, and the issue was gone after i set some of those TM settings back to stock. Do you have the issue on power downshifts as well ?
    Do you have a log to see if it's the same thing i was seeing in my logs ?
    Yes what I call power downshift. You mean like when I kung fu kick the gas as you call it? lol When I'm cruising along in 6th about 45 mph and stomp it is when this happens for me. Sometimes it will actually chirp the tires from deceleration and then after a brief pause start accelerating strong. The whole time my foot is on the floor. It’s as though the butterfly valve gets closed off briefly. I've tried factory settings on all the switches we've talked about - nothing seems to make it go away. But if I load my factory engine settings or vector's tune the problem goes away. It just really seems to be in the engine settings. If I give it part throttle and then hammer it, it downshifts awesome! Attached is my current TM settings.
    2009 hot white G8GT - Vararam, HSRK, street tuned, Kooks longtube headers and x-pipe. 12.675 @ 112.05mph.

  12. #12
    Tuner
    Join Date
    Jul 2011
    Location
    Fort worth, TX
    Posts
    126
    Quote Originally Posted by Mark Wheeler View Post
    Yes what I call power downshift. You mean like when I kung fu kick the gas as you call it? lol When I'm cruising along in 6th about 45 mph and stomp it is when this happens for me. Sometimes it will actually chirp the tires from deceleration and then after a brief pause start accelerating strong. The whole time my foot is on the floor. It’s as though the butterfly valve gets closed off briefly. I've tried factory settings on all the switches we've talked about - nothing seems to make it go away. But if I load my factory engine settings or vector's tune the problem goes away. It just really seems to be in the engine settings. If I give it part throttle and then hammer it, it downshifts awesome! Attached is my current TM settings.
    I dont know if it makes a difference but I have the speed cntrl terminate set to immediate and all my tip in torque management set to no throttle
    15 C7Z M7

  13. #13
    Tuner in Training
    Join Date
    May 2012
    Location
    Washington DC
    Posts
    23
    Well you're not alone in this problem, bluegoat. Ours is doing it as well, and in fact it does it twice in a row before it finally steadies up at WOT. Check this out. Waiting to hear back from tranny guys but will try the torque management switches.
    Cheers,
    Rick Robinson
    American High Performance
    Lorton, VA 22079
    703-339-7412
    http://www.americanhighperformance.com


  14. #14
    Ok I'll play.. I have the same issue with mine during a gas pedal "karate chop". If I tip in enough to kick out DOD and the TCC then go wot it is beastly. But, if I go straight from cruise speed there is about ~1 sec delay befor the downshift and then the feeling of what I can only describe as power being ramped back in after the shift completion.

    Currently my TM is disabled but Im not against turning it back on. However Im pretty new to tuning and I dont understand how to manipulate the tables. I started adding it back in last night by putting the TM drop down boxes like my stock tune and the shift torque factor values to .1 which I understand is 10% TM correct? But there are 3 other tables below it that Im not sure what to do with. There is an adder a cold and a multiplier iirc. Im just wondering how you guys are setting yours up for different amounts at wot and etc. Thanks for your help in advance!
    Squirrel stuff

  15. #15
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    Wanted to update my thread because I didn't realize I wasn't showing what changed in my tune to fix this issue. I wanted to show one of my peers exactly what I did today, and came to realize I never posted it. Crap, sorry about that, here is what I did



    Uploaded with ImageShack.us
    Last edited by bluegoat06; 07-18-2013 at 01:59 AM.

  16. #16
    You know its funny I remember reading this and thinking "I don't have that issue" now I know why. Mine is set the same way lol!!!
    Squirrel stuff

  17. #17
    Tuner
    Join Date
    Mar 2004
    Location
    British Columbia
    Posts
    90
    Image isn't working, can you give more details?

  18. #18
    Advanced Tuner
    Join Date
    Feb 2006
    Location
    Rancho Santa Margarita, CA
    Posts
    905
    There, is working again, Imageshack glitch I guess.

  19. #19
    Tuner
    Join Date
    Mar 2004
    Location
    British Columbia
    Posts
    90
    Thanks for that ^ I'd kept most of those values stock, so similar to your current settings, with Limit Tqmgt set high enough to disable. I'll try reenabling the master torque management switch on the neutral skip down.

    If traction control is turned off, it'll downshift awesome 6-2 or 3-1 and off it goes, but with traction enabled it bogs for a second and then goes, especially if it flaires and chirps the tires, at which point I'll see stability active on the display.

  20. #20
    Potential Tuner
    Join Date
    May 2016
    Location
    Trenton MI
    Posts
    1
    I know this is very old lol, but I am having the same issues and making changes to the tip in downshift and skip downshift also flare downshift and skip downshift switching from no throttle to throttle only would this be correct? bluegoat06?