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Thread: Please help with LS2 conversion

  1. #1
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    Default Please help with LS2 conversion

    I have been reading this forum for a while and it's time to ask for help.
    We installed an LS2 w 4L60E from a 05 GTO in a 91 Z28. We had speartech do the harness for the conversion and it's a stock drivetrain with headers.

    Now the problem, WHen you go past half throttle in low gear the computer will not let the throttle open more then 40-50% after the car shifts in to second gear the throttle opens all of the way and the car will rip! Jessie at wait4me has been a great help to me but I know he has to be one of the busiest guys in the planet so I hate to bug him.
    I have the traction control disabled and have tried many things in the engine and trans tune with no luck. Any input would be greatly appriceated.

    Jason

  2. #2
    Lifetime Member GMPX's Avatar
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    Jason, sorry to say but I already spoke to Jesse about that as it was pretty weird....but I did really have any idea what it could be either.
    I no longer monitor the forum, please either post your question or create a support ticket.

  3. #3
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    Is that a torque limiting thing? Jesse probably asked you this, wonder if the torque limiting tables in the ECM are forcing the throttle to stay at 40-50% then once the shift occurs the limiting tables allow 100% engine power so the throttle flies open. Can you pull the tune from it, or do you not have EFILive?

    Since its an 05 LS2 Im assuming its an E40 ECM controller, check table B2514 if you can pull the tune. Its under Engine->Traction Control. In my 08 E67 ECM you can limit TQ in individual gears with table B2514, looks like its just called something different in the E40. If in first gear it is restricting the delivered TQ this could be your problem, but I cant say for sure. If you can post the tune up that'd help (if you can pull it first).
    Last edited by ScarabEpic22; March 18th, 2009 at 06:06 PM.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  4. #4
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    Erik, that complete table in all of the gears are maxed at 8192. I have the shop version of EFI I will try to post the engine and trans tune in a few minutes.

  5. #5
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    Here is the engine tune.
    Attached Files Attached Files

  6. #6
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    And the trans tune if it helps.
    Attached Files Attached Files

  7. #7
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    IS there ant way to change the tune so the t/b opens when the throttle pedel is pressed and disable any fail safes? I know I'm grasping but I need to get his car done and dont know where to go from here. Would a log file help and if so what pids should I select?

  8. #8
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    I just unplugged the tcm and tried to free rev the car in park and the throttle is opening slow as it does when the car is in gear, plugged it back in and in park the revs to the moon quick. So it makes me think it's something in the trans tune,I just dont know what.

  9. #9
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    I think its still in the ECM calibration, this shows there's some parameter in the ECM thats restricting the revs in gear. This is ECM stuff, the TCM is just saying "Im here" when you plug it back in so the ECM knows the trans is in P/N or in gear. And when its in gear its messing up, I changed some TM parameters and one trans input shaft torque value. See if it makes a difference, Im just throwing ideas out there.
    Attached Files Attached Files
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  10. #10
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    Erik , thanks fo your help!! Last night I found that for some reason the prndl switch on the selector shaft of the trans is showing p in park r in reverse 6 in neutral and n in any of the drive gears so I tiook the prndl swith off off an SSR I have here and plugged it in .Turned the selector thru the gears and got the same readings as the one on the car. So I put it in park on the swith and the car revs in or out of gear and smokes the tires thru 3rd gear on the street. Only question I have now is if the selector switch is in the park position will this mess with in gear, in park tables?

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