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Thread: Have we been doing autove wrong?

  1. #1
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    Default Have we been doing autove wrong?

    So I have been working on my autove tune with lc-1 and I just don't understand exactly it is supposed to work. We are supposed to be putting the ECU in OLSD and when we do we run off of B3506 and I get that but what I don't understand is that above 60kPa we start changing the commanded ratio which means the LC-1 that is calculating the BEN for 14.62 is now being fed bad data from the ECU. If you log commanded air fuel ratio (GM.AFR) you can see it moves around when it should be steady. Any input?

    I have attached my tune files with corresponding log files.
    Attached Files Attached Files

  2. #2
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    I'm on my phone, so I can't open the tunes or logs. The BEN will account for changing AFR based on your open loop table or PE modifier. You should be commanding a richer mixture above 75-80 kpa. And the BEN will account for that.
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

  3. #3
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by GMC383 View Post
    So I have been working on my autove tune with lc-1 and I just don't understand exactly it is supposed to work. We are supposed to be putting the ECU in OLSD and when we do we run off of B3506 and I get that but what I don't understand is that above 60kPa we start changing the commanded ratio which means the LC-1 that is calculating the BEN for 14.62 is now being fed bad data from the ECU. If you log commanded air fuel ratio (GM.AFR) you can see it moves around when it should be steady. Any input?

    I have attached my tune files with corresponding log files.
    Yes, OLSD (you should see zero LTFT's, and a MAF DTC).


    Yes, B3605.

    The BEN is not calculating the BEN for 14.62... take another look at how it is defined (using LC-1 as example): {CALC.AFR_LC11.AFR}/{GM.AFR}

    GM.AFR comes from whatever the commanded fueling is (i.e. from B3605 when PE is not actove, and from the richer of B3605 and B3618 when PE is active).


    So yes, GM.AFR moves around, but then BEN pid uses this in its calculation.

  4. #4
    Joe (Moderator) joecar's Avatar
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    I prefer to use GM.EQIVRATIO instead of GM.AFR because EQIVRATIO does not depend on the stoich AFR of the fuel you're running

    ( for example, tune file stoich is typically set to 14.63 or 14.68, wideband stoich is set to 14.7 for some and 14.5 for others, fuel ranges from 14.1 to 14.7 )


    I use this BEN pid (using V2 wideband serial comms): {EXT.WO2LAM1}*{GM.EQIVRATIO}


    both EQR and LAM are independent of fuel's stoich AFR (you still have to set B3601 to match the fuel you're running).

  5. #5
    Joe (Moderator) joecar's Avatar
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    In your tune files, you have B3605 at EQR 1.1338 and B3618 at EQR 1.0039...

    both of these are too lean for WOT...

    set B3618 to EQR 1.18.

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    I have two different tunes, one with the correct B3605 and one with 14.62 AFR all the way across. I understand what you are saying now. I didn't realize that it considers the commanded AFR. That would explain why I got the same results either way.

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    so are you telling me to set B3618 to 1.18 even though I am still doing OLSD tuning?

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    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by GMC383 View Post
    so are you telling me to set B3618 to 1.18 even though I am still doing OLSD tuning?
    Yes, EQR 1.18 (which would be AFR 12.4)... to be sufficiently rich/safe at WOT load.

    Or, you could set the high load columns of B3605 to EQR 1.18.

    But, I'd do B3618... so when you go back to CL you will be safe.

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    Ok I now understand how the BEN will take into account the commanded fuel. Maybe the autove tuning tutorial should be corrected.

  10. #10
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    Quote Originally Posted by GMC383 View Post
    Ok I now understand how the BEN will take into account the commanded fuel. Maybe the autove tuning tutorial should be corrected.
    lol YA think?? I have been fighting similar issues, I'm not an engineer or a programmer, so I HAVE to take this stuff at face value!!

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