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Thread: Low idle, stalls intermittently when warm. xb12r

  1. #1

    Low idle, stalls intermittently when warm. xb12r

    I just purchased a used 2008 xb12r. It has a K&N, stock airbox, breather reroute, spec ops pipe with an EBR ecm for that set up.

    I put in a new set of NGKs, TPS reset, and pulled some data from ECMspy. This is what I'm getting.
    It starts no problem,but the idle isnt smooth. It sounds like its misfiring, once it warms up it idles fine and the idle drops to 1075ish. I'll ride it for 15 minutes or so, once its at operating temp and it will have a low idle and die at stop lights. When i try and give it fuel to keep it alive it will hesitate, cough, then run fine once i start moving again.

    CLT-175
    IAT corr-98%
    WUE-103.2%
    TPD-3.8
    AFV-100
    EGO corr- 81.7.%

    Here is a screen shot of some other data pulls.Screenshot (11).jpgScreenshot (2).jpgScreenshot (10).jpgScreenshot (12).jpg

  2. #2
    So, i got some feedback from a different post via FB. It looks like the previous owner had the AFV locked at 100. I changed the parameters to low of 85 and high of 120. I the bike now idles much better, but I have some noticeable flat spots when im accelerating. The AFV is now 85.6 which im aware is low, now what would cause a low AFV like this?

    I checked my intake seals and they are ok. I have no fault codes or historical codes. The IEV is functioning as it should. This is where I'm at now.Screenshot (19).jpg
    Last edited by patrickXB; 05-21-2021 at 04:48 PM.

  3. #3
    Senior Member Cooter's Avatar
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    IMO, jumping that deep into the magic black box without even checking the basics like above ^^^^ is a recipe for frustration. Start at the beginning, the basics... go through each step, and you WILL find the issue.

    Your AFV at exactly 100.0 tells me that the magic black box is probably running "Open Loop" only. Meaning it has been neutered and can no longer adjust itself. Running OL also means the magic black box can't tell you whats wrong, because you can't use AFV (a global map modifier) as a main clue to what the engine is seeing or how to correct it. Is it running lean? rich? You don't know, because IT doesn't know. All your fuel injection technology has now been made a carburetor. Carburetors are great and all, but it is fuel injections ability to adjust itself that makes it better, and it looks like someone turned that function off

    EGO correction should be near 100. That is also a global map modifier and currently your magic black box is pulling almost 20% of fuel from your bike and that is a BIG CLUE to diagnosing whats wrong.

    If you want to continue bouncing around in the magic black box instead of checking the TB seals, ECMSpy has a very detailed instruction manual that will explain the pages of info you posted and theres a TON of threads with the same questions. No need for it all to be re-written here. Good luck! Post up what you find and hopefully we can get you sorted.

  4. #4
    Senior Member Cooter's Avatar
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    That explains a lot. The AFV dropping to the lowest limit means the ECM is seeing a very rich condition and pulling a ton of fuel out. Are your running O2 voltages correct? Are the readings lazy? Go through what would make a bike run rich or what would make the ECM see a rich condition. Bad sensor, leaky injectors, the map itself or the targets could be set rich, things like that.

  5. #5
    Im getting oscillating voltages between 0.08 and .7

    I should have included my completed troubleshooting before posting. Intake seals are ok, IAT, o2 sensor, and throttle body seem ok. TPS resets have been done, and my TPD is normal. Ive checked all of my grounds and wiring harness with no issues found.

    As far as whether my fuel maps are rich, thats all greek to me. I can post the ones i pulled from ECM spy, but someone will have to tell me what it shows.

    Screenshot (14).jpg
    Last edited by patrickXB; 05-21-2021 at 06:05 PM.

  6. #6
    Ok, Ive finally found the cause of my issues. It seems that the ECM on this bike was an original EBR ecm that the previous own tampered with. The AFV was locked out to 100. After I unlocked it and changed it back to stock parameters, the AFV dropped to 85. After looking through the values and comparing them to what should have come from factory i found that the Front AFV value was 85, and the rear was set at 100. I set them both to 100, voila. My AFV values are now 95-98, and it runs and idles like a dream.

    If anyone has ECMspy screenshots of a well running 08+ xb12 i'd love to see them, that way I can ensure the rest of the setting on this ECM are as they should be. (rather than ask what each and every value should be) The fuel maps, timing, and the idle are all within spec.

    Thanks for all the info tracking this down!

  7. #7
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    bro straight up its your voltage regulator rectifier

    had the same issues Replaced my Stator, voltage regulator Main fuse and battery she fires up sexy now no stalls when warm

    i replaced intake seals cylinder temp sensor timing sensor banks sensor coil pack spark plugs and wires none of those problems were the fix but could very well give you the same symptoms if faulty

  8. #8
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    That was an issue resolved on one Buell. That does NOT mean it applies to EVERY Buell.

    Although electrical issues can cause a myriad of 'strange' problems. A faulty VR has NOTHING to do with an ECM compensating a low EGO fuel map correction.



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