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Thread: need help logging afr error

  1. #1
    Potential Tuner stl2slo's Avatar
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    need help logging afr error

    I'm sure this has been covered a million times but I just installed a wideband and am trying to log afr error to tune the 've table. I can log the wideband but not really error. Please help me with what I am missing.
    98 Z28. L92. 4l80e stock bottom end. Ported heads. Pat g cam trying to tune it sd

  2. #2
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    You need to air fuel ratio hi resolution in the table display. Then for your user defined parameter log the wideband/ commanded afr. I recommend tuning in lambda which is much easier to use. Lambda= 1.0 will always be the stoich for whatever fuel your using. Remember when tuning VE to hit as many cells as you can in steady state to get accurate results
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  3. #3
    Advanced Tuner blownbluez06's Avatar
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    Quote Originally Posted by 01SLPSSM6 View Post
    You need to Commanded air fuel ratio hi res in the table display. Then for your user defined parameter log the wideband/ commanded afr. I recommend tuning in lambda which is much easier to use. Lambda= 1.0 will always be the stoich for whatever fuel your using. Remember when tuning VE to hit as many cells as you can in steady state to get accurate results
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  4. #4
    Advanced Tuner blownbluez06's Avatar
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    It is absolutely not necessary to play the lambda game. If you bought a typical wideband kit, you only need to understand 14.7 is the stoich value for any fuel. E85, Methanol, Propane, CNG?, you want to see 14.7 on that display for stoich no matter what. The target WOT values vary.
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  5. #5
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    Quote Originally Posted by blownbluez06 View Post
    It is absolutely not necessary to play the lambda game. If you bought a typical wideband kit, you only need to understand 14.7 is the stoich value for any fuel. E85, Methanol, Propane, CNG?, you want to see 14.7 on that display for stoich no matter what. The target WOT values vary.
    I suppose, however it would be misleading.
    E.g. 50% gas, 50% meth.......10.55:1 is the actual stoich occurring in the engine.
    I prefer lambda as it allows easier percents and math use.
    Last edited by smithers; 07-13-2013 at 01:10 PM.

  6. #6
    Advanced Tuner blownbluez06's Avatar
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    Quote Originally Posted by smithers View Post
    I suppose, however it would be misleading.
    E.g. 50% gas, 50% meth.......10.55:1 is the actual stoich occurring in the engine.
    I prefer lambda as it allows easier percents and math use.
    Only misleading if you care what your mixture and therefore your actual, true AFR, which technically matters none at stoich. Put another way, someone focusing on X% of this fuel and X% of that fuel has no practical value and confuses many since your sensor doesn't know or care what the actual is. You would target 14.7 on your display regardless of the mixture of fuel, I consider it simple. If someone were already using Lambda, I would say "continue on". Someone accustom to using AFR based on their gasoline wideband, I say the same "continue on and continue looking for the 14.7 value on your display at stoich regardless of your fuel mixture"
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  7. #7
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    I prefer it based on lambda being 'easier for calibration'. Meaning, Lambda is 1.02, your 2% off - done. vs reading 14.98 and needs to be 14.7. you now have introduced extra calculations and steps. But I get what you are saying.

  8. #8
    Potential Tuner stl2slo's Avatar
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    back from the dead still cant log the error. I am logging commanded af high res and the wideband
    Can I get a screen shot or something of the histogram file?
    98 Z28. L92. 4l80e stock bottom end. Ported heads. Pat g cam trying to tune it sd

  9. #9
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    Bump , I'm having a similar issue . But I'm getting the % error for 14.7 . Then when I do wot / pe mode it thinks the air fuel error is way off .

    How do I set up a histo to correct commanded af vs just 14.7