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Thread: Feels like VTEC --- 07 TBSS with a 408

  1. #1

    Feels like VTEC --- 07 TBSS with a 408

    So I got this 2007 TBSS in from Colorado, Built 408 engine with stock 243 heads, green top injectors, ls7 throttle body, ls7 MAF, Edelbrock Hi ram intake manifold, cam specs are on the high 239/246 .623/.615 - 114 lsa
    The main concern, is that it has no power until it hits 5900 - 6000 rpm, it feels like vtec when it gets to that rpm. After looking at the logs, i noticed that the throttle % is erratic and even with the pedal mashed down, it shows less than full throttle and all of the sudden the throttle body opens up fully...
    The truck was originally tuned with HPtuners and EFI live to do some of the paqrameters for the converted 4L80 transmission.
    I have checked wiring, swapped tbodies, check continuity on wires and connectors and can't find anything wrong. I even replaced the throtttle pedal with sensor thinking it might have been an intermittent contact, but still no luck....

    Any ideas? Attached is
    a copy of the tune
    Attached Files Attached Files
    09 Pontiac G8GT LSA conversion & cammed (HP Tuned)
    07 Trailblazer SS Cammed & Nitrous Fed (HP Tuned)

  2. #2
    looking for the log files, don't know where I saved them
    09 Pontiac G8GT LSA conversion & cammed (HP Tuned)
    07 Trailblazer SS Cammed & Nitrous Fed (HP Tuned)

  3. #3
    found the log
    Attached Files Attached Files
    09 Pontiac G8GT LSA conversion & cammed (HP Tuned)
    07 Trailblazer SS Cammed & Nitrous Fed (HP Tuned)

  4. #4
    Screen shot, accelerator was pressed 100% from 6mph and never let off until 67mph.
    Attached Images Attached Images
    09 Pontiac G8GT LSA conversion & cammed (HP Tuned)
    07 Trailblazer SS Cammed & Nitrous Fed (HP Tuned)

  5. #5
    Ended up being a Harness/tcm issue. We got a New TCM for a 4L80 and harness from leftcoast32 and all the issues went away
    Running very strong now!
    09 Pontiac G8GT LSA conversion & cammed (HP Tuned)
    07 Trailblazer SS Cammed & Nitrous Fed (HP Tuned)