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Thread: AFV Questions

  1. #11
    Senior Member Cooter's Avatar
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    Remember: AFV is simply an adjustment the ECM does. AFV sticking and staying exactly at 100 would be a rare anomaly (and not normal). Yes, it is an important clue when things go awry, but the fact it's adjusting is a good sign.

    119 is a bit outside of what I'd like to see (it's adding 19% more fuel). The factory limits of that adjustment are 70-140 from what I see on most OE programs so you're well within that range.

    This is the important difference between a open loop tune (non adjusting 'carburetor') and closed loop (the Fuel injection ECM sees what the engine is doing and +/- accordingly several times a second). OL is totally OK for a closed circuit where dramatic throttle changes are the norm and split seconds matter, but for the rest of us, a CL tune allows the ECM to give the engine what it needs to run the most efficiently it can in all situations.

  2. #12
    Senior Member Cooter's Avatar
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    Quote Originally Posted by njloco View Post
    Winter is the season you miss when living in Florida or on the wrong coast.

    When I moved to Florida the next THREE hurricanes went to New Jersey.
    Screen Shot 2021-11-11 at 10.42.33 PM.png

    Sorry NJ

  3. #13
    Senior Member BuellyBagger's Avatar
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    Quote Originally Posted by Cooter View Post
    Remember: AFV is simply an adjustment the ECM does. AFV sticking and staying exactly at 100 would be a rare anomaly (and not normal). Yes, it is an important clue when things go awry, but the fact it's adjusting is a good sign.

    119 is a bit outside of what I'd like to see (it's adding 19% more fuel). The factory limits of that adjustment are 70-140 from what I see on most OE programs so you're well within that range.

    This is the important difference between a open loop tune (non adjusting 'carburetor') and closed loop (the Fuel injection ECM sees what the engine is doing and +/- accordingly several times a second). OL is totally OK for a closed circuit where dramatic throttle changes are the norm and split seconds matter, but for the rest of us, a CL tune allows the ECM to give the engine what it needs to run the most efficiently it can in all situations.
    Ok then, that's pretty much where my thoughts were on it. Ill likely try the rev-mo tune and see if it reigns the afv in a little, possibly it's a bit richer tune?? Can always go back.

  4. #14
    Senior Member Cooter's Avatar
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    A closed loop enabled ECM will search for stoic while you're (95% of the time) normally riding/cruising no matter how 'rich' the tune is*.

    A 'rich' or a 'lean' map is referring to the open loop operation, OL basically only happens at WOT (thats why tunes are built and tested on a dyno at WOT only). As soon as you aren't at WOT, the ECM switches to CL and searches for stoic again. Thats why the 'tune' doesn't matter except that 5% of the time you are riding it hard. Furthermore the Buell ECM has a VERY wide range of adjustment (unless it's hobbled by a 'tuner'), using both AFV and EGO to correct the factory map for cruising the most efficiently it can.

    Ya, you're right BB. It's easy and free to swap them, might as well see what happens? There are benefits to having a good tune, but AFV sticking exactly at 100 won't happen. If you're using ECMDroid for the swap, be aware the ECM parameters change with the tune as well. That includes fan/temp settings, quick shifter enabled, O2 sensor settings, etc. So go through yours first and write down what they are so you can make them the same once you swap the new tune in, re-set both the AFV and EGO to 100, go ride it normally for 20 miles or so, then you can check what settings did what.


    *Oversimplification warning, I'm totally ignoring a 'tuner' changing CL targets because there is no reason on this planet that doing that is a good idea.

  5. #15
    Senior Member BuellyBagger's Avatar
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    Ten four! Thanks for the insight cooter



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