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Thread: '04 XB12S starts, then stalls within 20 sec every time

  1. #1
    First post... I need some help with an issue that came up out of the blue. I went and got fuel (93 octane as usual), rode home, parked the bike. Got up to ride to work and the bike started, then stalled within about 20 seconds. Started the bike again and it did the same thing. Two weeks later and still scratching my head. I tried a few things... Keep in mind NO check engine light at all. If I try to wrap the throttle and it will rev for a split sec, the spit and sputter and stall out after the occasional backfire and smoke coming out of the throttle body. Here's a couple of things I did.

    -Drain suspect bad gas and refill with 93 octane and Seafoam mix - NO CHANGE
    -Check for any shorts in wires - NOTHING
    -new plugs - NGK, non-IR - NO CHANGE
    -fuel is pumping, not sure pressure? Trying to get a gauge set up...
    -purchased cable for ECMspy, reset TPS a couple of times - NO CHANGE

    Here's where it gets interesting.... I found if I disconnect the ETS, the bike idles better (for almost 1 min, then dies). During that time, I can give the bike some throttle and it seems to be OK, then eventually dies. ECMspy did clue me into why this works. When I disconnect the sensor, it defaults the engine temp to -10deg C which calls for an extremely rich mixture on start up. I then decided to over-ride the closed loop and set the AFV to 150 (max value) and run the bike extremely rich. The bike would then idle fine, I could give it throttle and I even took it around the block. It ran somewhat normal at low revs, but could tell something not quite right. I realize this isn't a fix, I'm just trying to figure out where to go next. All I know now is that the bike only wants to run extremely rich (high AFV). I did recently find out in one of the posts that the vacuum port on the throttle body should be plugged. I'm going to plug this today when I get home and see if it helps...

    What should I do next???

  2. #2
    Senior Member
    Join Date
    Mar 2009
    Would like to bump this to the top since helping people is what this forum is about (I have learned a ton here). However, it sounds like you have tried many things. Anyone have anything for this? My guess would have been shorts or plugs...

  3. #3
    Senior Member
    Join Date
    Sep 2010
    Almost sounds like your fuel map is f'ed....PM me with your email address and I'll send you one of my maps for comparison of "correct" values. Also - what mods are done to your bike? I'll send you the timing map as well, just in case timing is off.

    Oh - in the mean time, do check your static timing.

  4. #4
    Senior Member ich's Avatar
    Join Date
    Oct 2010
    temp sensor failure, check all temp sensors.

  5. #5
    Senior Member lunaticfringe's Avatar
    Join Date
    Feb 2011
    AmishLand, PA.
    temp sensor failure
    that....or worse.....your ecm is bad

  6. #6
    Hope its not the ECM... I'm looking into the fuel pump assy. I dropped the pump out and found the screen all black and that it would hold water. I was going to just replace the screen, but since it was a job getting the pump out and the bikes 10 years old... I'm going to do a complete re-build and go from there. Should have all the parts in a couple weeks. I found a similar post to mine and his issue was in fuel delivery. He wasn't sure of actual component, just did the complete rebuild too. This seems like a good place to start just because all the ECM inputs I can check are OK and no engine trouble codes to go off of. Probably should have rigged up a fuel pressure check first... was hoping to find something obvious when I dropped the pump assy down. One more thing... if I disconnected the fuel line right after stalling, then charging the line the fuel never bursted out like I thought it should. It just trickled out. What was odd is that if I disconnected the line at the pump side and turned the key on, fuel shot out about 6 ft???

    Thanks to those who have posted! Please come back with anything else you think of.

  7. #7
    Senior Member Banshee77's Avatar
    Join Date
    May 2013
    I know this sounds dumb, but try running it with the gas cap left loose.

  8. #8
    I did actually try that... I tried a lot of "dumb" things and still no luck. I was trying to figure out why when I increase my AFV setting to 150% in ECMspy it runs(to some degree). I thought that if my pressure/flow was low, that increasing this value would increase my injector fuel output thus attempting to make up (a little) for the lack of flow/pressure. Does this make sense???

  9. #9
    BACK ON THE ROAD!!! Not sure which component of the fuel pump assembly did it (most likely pump), but after a complete re-build(pump, regulator, hoses, filter, strainer) of the assembly, the bike runs better than ever!!! Now if I can just figure out why I keep blowing the ACC 10A fuse??? Bought the bike used and all sorts of little suprises keep coming up :)

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