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Thread: 08' XB12X New ECM, won't start/idle -repost from troubleshooting thread

  1. #1
    Junior Member
    Join Date
    Mar 2016

    08' XB12X New ECM, won't start/idle -repost from troubleshooting thread

    Hi All,

    I could really use some help getting my ride back on the road. Here is the full story. My bike (08' Uly) started stalling while riding. Happened in a corner and when it came back the rear tire grabbed hard and I almost lost it. So, after a ton of testing I finally did the screw driver tap test on my ECM. Sure enough it would stall every time I tapped the ECM. So I ordered a replacement from ST. Paul HD via Ebay. Winter started so I figured I would just take the opportunity to do a bunch of work on it. Here is a list of what I've done:
    • Rotated the motor
    • Changed the rear rocker cover gasket
    • Double checked torque on all top of motor bolts
    • Rotated motor back up and double checked torque on all bolts
    • Installed a new fan
    • Traced all wiring back to confirm no opens or corrosion
    • Retaped wiring harness
    • Replaced clutch cable, but the new one snapped off so HD is sending me another
    • Changed plug wires
    • Installed a new ECM
    • Roughed up ground terminals and reinstalled ground leads
    • Double checked all electrical connections
    • Bought activation for ECMspy
    • Fectched and stored ECM values and then flashed (Software said no value change)
    • Ran these test on ECMspy: Fuel pump (pass), Front and Rear Coil (pass), Front and Rear Injector (Pass), Fan (Pass)
    • Performed a TPS reset - The Key on, Kill Switch on, Throttle on/off 3 times method

    The bike is fully reassembled (minus the clutch cable I'm waiting on from HD). It will not start. I'm in neutral, I hear the pump prime, but it just won't run for more then a half second. I can get it to run if I flutter the throttle, but it sputters and backfires and dies the instant I stop. I bought the activation for ECMspy thinking it would help, but so far it hasn't. AFV is 100% and the EG0 is 100%. Here are links to my saved map, eeprom, and logfile from ECMspy: If you need screen shots instead of the files let me know and I'll post them.

    Here is a video I made that shows the problem:

    Any help would be greatly appreciated! My new tires came today and I want to be out carving the canyon roads not staring at my bike in the garage.

  2. #2
    Join Date
    Feb 2011
    AmishLand, PA.
    i know nothing of screen shots and ecm values so of no assistance along those lines but appears you did everything correctly. question: a few months ago another board member posted up an almost identical scenario after he did a motor rotation for some maintenance and installed, as i recall, a replacement ecm. his predicament precisely same as yours. was narrowed down to mis-wiring a few components atop the motor and beneath the airbox base plate. are you absolutely certain the injector harness plugs and all other components that you unplugged are back together correctly?

  3. #3
    Junior Member
    Join Date
    Mar 2016
    Thank you for the reply. I'll double check all my wiring. I also got a tip to check the IAC. I was able to get it to run off the old ECM, but if the IAC is bad the old ECM might just be using historic data to make the adjustments and the new one can't do that because it lacks the historic data.

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