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Thread: 2012 Buick Regal GS big turbo. Stalling, lurching, etc.

  1. #1
    Tuner in Training
    Join Date
    Mar 2023
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    11

    2012 Buick Regal GS big turbo. Stalling, lurching, etc.

    Howdy. I'm helping a dude with a 2012 Regal GS with an S257 63mm turbo. He paid to have someone tune it and they did a poor job and even broke some parts.

    The guy says his car stalls and hesitates/lurches.

    I have attached his tune file and a series of logs from pulls, to duplicating the complaints.

    I'm entirely unfamiliar with the platform so I am hesitate to make any judgements/determinations. It would be great if the community can help this guy, he's already been taken advantage of.

    Thanks in advance.
    Attached Files Attached Files

  2. #2
    Tuner in Training
    Join Date
    Apr 2022
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    48
    Don't know how much help I'd be, but I would say a lot more channels need to be logged. Cylinder airmass, dynamic airflow, VE airflow, intake/exhaust actual and desired position, delivered/predicted/immediate torque, torque management advance, etc.

    Spark advance is going negative while idling which could account for the stalling/hesitation. Believe this happens when the engine makes more torque than the torque model wants/expects (too much airflow); this can be adjusted via the Virtual Torque under Edit (once airmass/cams/torque parameters are logged you can see where in the VT tables the torque is too low and bump these up).

    I'm pretty new to tuning so hopefully someone else can chime in. Good luck!

  3. #3
    Tuner in Training
    Join Date
    Mar 2023
    Posts
    11
    Quote Originally Posted by KillboyPowerhead View Post
    Don't know how much help I'd be, but I would say a lot more channels need to be logged. Cylinder airmass, dynamic airflow, VE airflow, intake/exhaust actual and desired position, delivered/predicted/immediate torque, torque management advance, etc.

    Spark advance is going negative while idling which could account for the stalling/hesitation. Believe this happens when the engine makes more torque than the torque model wants/expects (too much airflow); this can be adjusted via the Virtual Torque under Edit (once airmass/cams/torque parameters are logged you can see where in the VT tables the torque is too low and bump these up).
    I'm pretty new to tuning so hopefully someone else can chime in. Good luck!