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Thread: Aftermarket ECM, 6l90 shift funny now

  1. #1
    Tuner in Training Turbostangs90's Avatar
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    Aftermarket ECM, 6l90 shift funny now

    2009 CTS-V
    Car was fully tuned with stock ECM and 6l90 trans, and it performed very well.
    I have recently gotten rid of the factory ECM and replaced it with a MOTEC unit from John Reed Racing. I'm no longer using the MAF to tune the car, as it is now Speed Density. The MOTEC isn't directly controlling anything with the 6l90 TCM, as I still use the HP tuners to make changes to that.
    Now the transmission isn't shifting as it was with the stock ECM, mostly having a flare on the 2-3 shift. I'm curious if it is just going to require some finessing with the TCM tune to get it all dialed back in. I was thinking of maybe adjusting the oncoming pressure preset for the 2-3, or maybe just doing a trans adaptive reset to see if that helps.
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    Last edited by Turbostangs90; 09-20-2022 at 01:47 PM. Reason: file added
    2009 CTSV Sedan CRT
    TMS 427, Modified Huron Twin Kit, BW-S369s, Greg Good CNC Brodix BR7s, Lil Jon Turbo Cam, PTC converter spec'd by Dusty Bradford, ID1700s, FORE Fuel System, built 6l90

    1990 Mustang tuned using Holley EFI

  2. #2
    Senior Tuner
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    Is the motec on the can bus and is it configured to broadcast the torque over the bus for the trans to pick up? There is probably a load or torque table designed for that purpose in the motec. I suggest that table may need revisiting. And yes adapt reset preset is a good idea. I would leave oncoming pressure alone, if it worked fine before there is no need to change it. Just get the reported torque right.

  3. #3
    Senior Tuner mbray01's Avatar
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    Tcm needs proper torque signal, you need to ensure its getting the proper siganl, and that it is correct
    Michael Bray
    Rusty Knuckle Garage
    Slidell, Louisiana
    20yr Master Tech.
    Advanced Level Specialist
    Custom Car Fabrication, Customization, High Performance.
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  4. #4
    Tuner in Training Turbostangs90's Avatar
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    Motec is on the CAN bus. After doing some digging I found that it does have torque tables that can be adjusted to optimize the transmission performance. Thanks.
    2009 CTSV Sedan CRT
    TMS 427, Modified Huron Twin Kit, BW-S369s, Greg Good CNC Brodix BR7s, Lil Jon Turbo Cam, PTC converter spec'd by Dusty Bradford, ID1700s, FORE Fuel System, built 6l90

    1990 Mustang tuned using Holley EFI

  5. #5
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    Good. Go through your old logs and make a chart that matches the motec table and copy your reported torque into the motec table and hand smooth. If you've done a good job you won't need to reset / preset the adapts.

  6. #6
    Senior Tuner Ben Charles's Avatar
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    If anything go little high on the tq..