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Thread: 2003 XB9R Noob- engine cuts out questions

  1. #1
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    2003 XB9R Noob- engine cuts out questions

    Hi guys,
    Larz here, first Thanks for the add.
    I am noob to the Buell family and mostly restore Hondas but this was a deal I couldn't walk away from.
    Background...
    Got the bike a few months back with the clutch removed and supposed starter problems. I reassembled the clutch and drive and lo and behold everything seems to work as it should. Starter clutch is worn but no biggie for the moment.
    Rode the bike a few times with no problems (clutch does slip a tad) but no trouble to redline.
    Changed the plugs and did an engine clean up. Unfortunately I moved the throttle plate while cleaning the throttle body so of course it ran poorly and research indicated a TPS reset.
    Ordered a cable and downloaded ECMSpy. With a bit of fiddling was able to get that to work for TPS reset. Bike now idles 1050-1150 and in neutral revs freely to 7k.
    Try to drive the bike and as you apply throttle in first the engine dies (about 3-4000rpm) flat and Ck engine light illuminates but everything comes back if you pull in the clutch.
    Reconnect to ECMSpy and read trouble codes and I get AMC stuck open and AMC stuck closed. The XB9 service manual doesn't reflect the 21 code shown and I don't have the full code at the moment. I didn't see in the XB9 manual about the AMC. I don't have a valve actuator or cable (that I can find)...is it possible I have a xb12 computer? I haven't looked at the ecm itself yet either...
    I would appreciate your thoughts, Thanks in advance
    Larz
    Last edited by LarzFroMarz; 09-25-2018 at 06:18 PM.

  2. #2
    Senior Member Cooter's Avatar
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    Hi! welcome to the forum.
    Look at the ECM. If it has a single spade terminal between the two plugs, it is an XB12 ECM. But honestly that doesn't matter, they are able to run either bike with the right fuel program. I'm just curious if its been messed with.

    Moving the throttle blade won't cause a need for a TPS re-set. I believe you did not reassemble something correctly and I would check that first before messing with the ECM further.:
    The lower airbox cover needs to have the seemingly unimportant lower gasket installed properly. Its the big ring below the TB intake tube. Or you possibly caused an intake seal leak. Check the manual. You can get a free .pdf download from Buellmods.com or Buelltooth.com.

    Or you did something unknowingly wrong with ECMSpy. Unless you are building a fuel map from scratch, I would recommend using ECMDroid for simple tasks like checking codes, TPS re-set, swapping existing maps, and general diagnosis. The program is free on GooglePlay, and needs a wireless bluetooth connection. I like the dongle I got from Buelltooth.com.

  3. #3
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    The XB9 service manual doesn't reflect the 21 code shown and I don't have the full code at the moment.

    that's because NO XB9 ever built has IEV system so no reason to be specifically mentioned in the "9" manual.

    Try to drive the bike and as you apply throttle in first the engine dies (about 3-4000rpm) flat and Ck engine light illuminates

    one or more ground faults in conjunction with failing fuel pump producing minimal pressure.

    but everything comes back if you pull in the clutch.

    absolutely NO idea what "everything comes back" means but i'll tell you something i'm familiar with which probably nobody else in the world knows of: THAT IS A GROUND FAULT! how? the cable is intermittently completing a faulty ground circuit when you pull in the clutch lever.

    Reconnect to ECMSpy and read trouble codes and I get AMC stuck open and AMC stuck closed.

    how the hell can you retrieve IEV fault code #21 from a STOCK UNMODIFIED XB9 ecm????

  4. #4
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    Lunatic, thanks for your response.
    Let me clarify, I surmised the XB9 doesn't have that system on it, however since I know nothing about the bike before I got it I have no idea if it has stock ECU/ECM, I'm sorry you assumed that was the case. I understand its not in the 9 manual which is why I looked at the 12 manual to confirm the code.
    To give you an idea regarding the engine "coming back", as described, engine idles and revs freely in neutral, no engine light. Once in first gear and release the clutch and reach 2-3000 rpm the engine dies and the ck engine light comes on. Pull in the clutch and engine runs again normally, revs freely and the check engine light goes out.
    Sorry to make you read between the lines, I understand interweb diagnosis is difficult.
    That being said I'll look over the grounding and fuel pump systems ad see what I can find.

  5. #5
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    my pleasure Sire.
    to avoid unnecessary work and difficulties doing that work i'll tell you exactly what i'd do if the bike were in my shop before i commenced into ripping and tearing and throwing random parts at it:
    1-go thru every single ground connection on the entire bike. i've tirelessly listed them on here forever. THIS INCLUDES but is not limited to the ecm ground AND rear sub-frame connection at the frame spars. critical that be done!
    2-borrow or buy a known good STOCK UNMODIFIED ECM and try it. the ecm is the "heart" of your bike and you don't even know what you're working with. to not address that before proceeding past the grounds is pointless and utter waste of time.

  6. #6
    Senior Member Cooter's Avatar
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    Lunatic mentioned a failing fuel pump.

    I would agree. Checking pressure is a pita (49-51 psi), but necessary.

  7. #7
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    Follow up. Put a trouble free 30 miles on it last night. Bypassed the clutch interlock and everything works as its supposed to. I'll track down that system and find the short or break.
    Not Fuel pump.
    Thx

  8. #8
    Senior Member Cooter's Avatar
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    Didn't see that coming....

  9. #9
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    That Lunatic is a Buell wizard. That's a great no nonsense break down of back to basic trouble shooting. Good job John.

  10. #10
    Senior Member 34nineteen's Avatar
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    ^^^



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