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Thread: Turbo 5.3 stumble and dying

  1. #1
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    Turbo 5.3 stumble and dying

    Hello first off new to tuning LS stuff.. I have a turbo 5.3/th400 combo with summit turbo cam, decapped injectors and s475 turbo. 2bar OS running SD.. Been doing a lot research and have created a base tune to get the truck running, idles decent, cruises ok and gets into boost fine. But when coming off light throttle back the truck stumbles for a second and dies sometimes.. Can anyone point me in the direction to try and fix this.. Thanks!

    2bar base.hpt

  2. #2
    Tuning Addict 5FDP's Avatar
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    Is this a cable throttle body or drive by wire?

    You better be careful too, you have zero power enrichment and boost enrichment. Both tables are set to 1.00, which means stoich. You better set those up so it commands the proper fueling in boost. The whole PE tab needs changes.

    Do 90 map kpa enable, 60% throttle hot/cold, 1,000rpm delay, 105kpa for boost enrichment and setup both the PE and BE to have what you want for fueling. Like 12.5 for PE and 11.5afr for boost.


    This may or may not help but if you aren't running the stock transmission anyone, don't even change the transmission type. Leave it as is and disable all transmission related codes and abuse modes.

    Log files with good data are more helpful here too.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
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    Quote Originally Posted by 5FDP View Post
    Is this a cable throttle body or drive by wire?

    You better be careful too, you have zero power enrichment and boost enrichment. Both tables are set to 1.00, which means stoich. You better set those up so it commands the proper fueling in boost. The whole PE tab needs changes.

    Do 90 map kpa enable, 60% throttle hot/cold, 1,000rpm delay, 105kpa for boost enrichment and setup both the PE and BE to have what you want for fueling. Like 12.5 for PE and 11.5afr for boost.


    This may or may not help but if you aren't running the stock transmission anyone, don't even change the transmission type. Leave it as is and disable all transmission related codes and abuse modes.

    Log files with good data are more helpful here too.
    It is a drive by wire setup.. I have all the PE setting set to zero and was just using the VE table to do all my fueling adjustments. But I guess I should re think that? I am running a TH400 and have abuse mode disabled and no codes.. I can get a data log in the morning. Thanks for the fast responds

  4. #4
    Tuning Addict 5FDP's Avatar
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    If you ask me that's not a good way to tune it.

    When using a wideband sensor with a wideband error it's always going to report the error against the commanded lambda or AFR. Doesn't matter if it's running at stoich or if the commanded AFR is at 11.5. Doing it the way you have it, it's going to ask for stoich all the time but you are just adding and adding fuel to the VE to make it richer.

    My comment about the transmission is that sometimes the computer doesn't like when you change things that shouldn't/can't be changed. That operating system was never offered with a non-elec auto transmission. It's the same thing with 4L60 to 4L80 swaps, you can't just change the drop down and call it good because the base file is still a 4L60e. I tend to not change that table and leave it as it was to prevent weird background issues with idle or limiters.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  5. #5
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    Quote Originally Posted by 5FDP View Post
    If you ask me that's not a good way to tune it.

    When using a wideband sensor with a wideband error it's always going to report the error against the commanded lambda or AFR. Doesn't matter if it's running at stoich or if the commanded AFR is at 11.5. Doing it the way you have it, it's going to ask for stoich all the time but you are just adding and adding fuel to the VE to make it richer.

    My comment about the transmission is that sometimes the computer doesn't like when you change things that shouldn't/can't be changed. That operating system was never offered with a non-elec auto transmission. It's the same thing with 4L60 to 4L80 swaps, you can't just change the drop down and call it good because the base file is still a 4L60e. I tend to not change that table and leave it as it was to prevent weird background issues with idle or limiters.
    Oh ok I think I understand it now.. I changed the PE and BE setting to ones you adjusted and changed the transmission settings back to stock. I will flash it in the morning and see what it does!

  6. #6
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    I have the same setup as you. Have you come up with a good tune?