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Thread: VE Tuning Problem with P0068

  1. #1
    Tuner in Training
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    Apr 2006
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    VE Tuning Problem with P0068

    I am just starting to tune a 2005 CTS-V with an LS6 engine in it.
    Modification are a K&N CAI, 1 7/8" long tube headers and a full cat back exhaust.

    I am equipped with a wideband on this particular car and I have all my %AFR Error via the wideband set up and was going to start tuning the VE tables.

    After I flash the ECM, usually the 2nd or 3rd key cycle the ECM will set a P0068 and a reduced engine power message. Car runs like crap obviously and I dont get anywhere.

    I have tried to disable the P0068 diagnostic code to report no SES light but that doesnt seem to work.
    If I reflash the ECM with the stock calibration, code doesnt show up and I have no issues other than being unable to tune the VE tables.

    Is there something I am completely missing?

  2. #2
    Tuner in Training
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    Apr 2006
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    I did try increasing the P0068 Calculated Airflow Table by 15%. Still does the same thing...

    Any help is appreciated guys, thanks!

  3. #3
    Senior Tuner 5_Liter_Eater's Avatar
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    Nov 2005
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    Houston, TX
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    I typically end up disabling the P0068 test but only need to on vehicles that were not blown from the get go. You can try playing around with the delta airflow and max airflow but it's easier just to disable it.
    Bill Winters

    '05 Corvette - Iron Block 408 & TTIX - 928 RWHP / 926 RWTQ @ 21#

    "When life hands you lemons you upgrade to a C6." - Me

    Always post a tune and a log when asking questions.

  4. #4
    Tuner in Training
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    Quote Originally Posted by 5_Liter_Eater View Post
    I typically end up disabling the P0068 test but only need to on vehicles that were not blown from the get go. You can try playing around with the delta airflow and max airflow but it's easier just to disable it.
    I looked for disable function for the P0068 but could not find one. Where is it? This is for a LS6 so it may be different.

    I finally got the car to be driveable by maxing out the whole table of Calc. Airflow to 4 g/cyl.

    I was seeing a 20-25% LTFT before I started tuning so maybe the airflow did really increase enough to cause the P0068 to trip.

    After I finish the VE and MAF tuning I would like to adjust this table back to a real table, does anyone have any experience doing this?

    Thanks!

  5. #5
    Tuner in Training
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    Jul 2008
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    engine diag...

  6. #6
    Tuner in Training
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    Apr 2006
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    It could be but I haven't had this problem before and it only will set the code when I force open loop speed density.
    I found I only had to adjust the table a small amount after playing with it for a while and didn't have to max it out at 4 g/cyl.
    I have since started doing a MAF calibration and put the stock table back in, no issues yet. I am keeping my fingers crossed.