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Thread: 6l80 fuel cut during shift

  1. #1

    6l80 fuel cut during shift

    Turbo 16 5.3 A6, 3k stall. did my shift/lockup points with Bluecat. I've tried a ton of things to make 1-2 shift happen in a reasonable time but it does fuel cut for torque management and the truck shifts take terribly long. I don't see any settings to eliminate it besides shift time? Also in logs current gear doesn't seem to follow reality. shifts are 500+ rpm before the limiter fwiw

    slow 1-2-3.hpl
    Last edited by UMSTuning; 02-27-2019 at 08:27 PM.

  2. #2
    Advanced Tuner lt1z350's Avatar
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    its doing some of the stuff my 6l80e 07 swap is doing. So I compared our input and output speed and they are close and I know for a fact mine are wrong as when im in lock up running in 6th gear its not close to having output rpm and input rpm the same. SO Im attaching my channel list and do me a favor. Load it up and log your truck for me so I can compare a bunch of your parameters to mine as my list has stuff I need. In the process of figuring out my issues ill fix yours too.
    He is my known issues. I have a 2007 tahoe it was a 4l60e with that style t case. So when I changed over to the 6l I used my old t case so when the new tune changed os in my ecm the input speed and out put speed ratios changed which makes it not calculate the correct gear ratios and shift funny. I get the same delayed shifts at wot and I see yours is commanding 2nd gear like 800 rpm before the shift and its not happening so its like I said commanding it or I thinks its shifted already.
    is yours delaying on normal driving? Seems to shift late like a pause shift?? Hard to describe but it doesnt feel right. Its like its not pulling into the next gear but more like its holding the gear too long and says ok shift nnnnnnnnnnnnnnnnnnoooooow rather then shift now. then sort of lunges to the next gear. Any way maybe you changed something the gear in the rear or somehow your tune changed. So post up the current tune make sure it has the current trans attached too if been changing it around. I need to see all your ratios on the ecm side and calibration stuff. Then look at some trans side stuff. I have been looking over a lot of vehicles and now see yours doing the same so maybe now can figure this out off a log from you. Thankks so new log with my channels and the current tune
    Attached Files Attached Files
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  3. #3
    Advanced Tuner lt1z350's Avatar
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    Mar 2014
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    Dandridge, TN
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    also sorry to mention can you do a few normal driving upshifts let it make 1-6 and go into lockup just normal driving and do a wot pull on it to a few gears. I can get rid of that tm timing cut but you have to have some in it or you might tear it up. I have my 2017 zl1 from -25 degrees stock to now dips to 10 degrees or so rather then holding the full 25 degrees of timing its running at wot so it drops some torque to not damage the trans on the shifts. Also how are they at normal driving? sloppy or quick? if you had to add lots of pressure to it to make it shift decent for just normal driving then you need to add like 30 percent ot virtual torque so it adds the correct pressure to the tcm as its not seeing the extra power the engine is making so not enough hold on the clutches.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150