My F800gs STALLS LIKE ITS RUNNING OUT OF GAS!

Discussion in 'Parallel Universe' started by chunter, Jan 3, 2009.

  1. dirtysouthjacket

    dirtysouthjacket Been here awhile

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    If you really start banging your head against the wall... Double-check your side stand switch. Mine had an issue and at first I thought it was fuel related. Dealer replaced under a recall for my 2012 two years ago.
  2. RedHawk47

    RedHawk47 Adventurer Supporter

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  3. slide

    slide A nation with a future

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    Oh, well, it never faltered at high throttle settings so I guess the fuel pump solution is out. I just got back from 20 miles and not a stutter. The difference may be the ambient temp then was over 90f while now it was maybe 70f.

    I agree on those factory manuals. I once got one for an airhead in the way back when. The book was filled with things like, "While you are machining the valve face, order your assistants to...." and so forth. Most of it was incomprehensible to me which is why I'd hoped for a Haynes or Clymer both of which I've gotten good results from in the past.

    It's a long shot but I am now running it as low on fuel as I dare and then I'll fill up again and hope it's the fuel.
  4. slide

    slide A nation with a future

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    Thanks, JR. No, the problem occurred twice while idling at a light but a few dozen times (in maybe 80 miles) always with light throttle settings. High hg throttle settings never faltered.
  5. slide

    slide A nation with a future

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    Good tip. My DRZ had this when I got it really moving in the whoops or other high vertical loads. Since mine's a '12 too, maybe that's the issue. Since this was sold by the dealer, I'd expect he checked for recalls but you never know.
  6. slide

    slide A nation with a future

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    Gee, read the entire thread and am amazed that the list of suspects is enormous. I was interested in reading your experience in temps is the same as mine. The problem developed when the ambient was well over 90 and hasn't returned today riding in temps around 70.

    Can you now ride fine in higher temps or haven't you tried?
  7. RedHawk47

    RedHawk47 Adventurer Supporter

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    After replacing the fuel pump the bike ran fine a high temps (and low). Never had a problem when on the throttle, only when off the throttle: slowing for a stop, off the throttle for even a slight downhill, or at a stop. Scariest was when making a left turn, after getting up to speed, backing off the throttle and having it die - pull in the clutch, coast, and hope you get out of the way of the oncoming traffic. That happened at least twice - but I just remembered a worse incident. I had pulled out to pass on a 60 mph two lane. When I was even with the truck I had enough speed so I backed off on the throttle, and it stalled. There was an oncoming vehicle!!! Fortunately, before I could put on the brakes, it fired up and I could complete the pass.
    Dan
  8. slide

    slide A nation with a future

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    Still scary thoughts, Dan.

    Here's an update. I just got back from the dealer who sold me the bike a few days ago. The service writer said it sounded like a bad fuel pump to him but he can't be sure. He said he'd do a thorough diagnostic if I could leave it. I had ridden maybe 40 miles today by then w/o a hiccup but all in sub 80 temps. I said I don't see this as anything but a waste of your time until I can get the failure to repeat. He agreed. My point in reporting was to get on the record that the bike I was sold may have a life threatening defect. I'm expecting wear and tear on a used bike but not a condition which can kill me.

    I bought a bottle of BMW fuel cleaner while at the dealership. I rode the bike down as close to empty as I dared and then filled up with a known good Shell source and added the cleaner. I'm hoping this is a combo of ethanol and water making grunge. The last fueling I did before the trouble started was at a station in Vaughn, NM which is one inch away from being a ghost town. I'm hoping I got some bad fuel although I did run 100 miles w/o trouble after filling up.

    If the issue resurfaces, I'll take the dealer up on the service check.
  9. MFGamesta

    MFGamesta Been here awhile

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    OK. I hope someone can help. I have a 2015 F800GSA with 25K miles. About 10K miles ago, I put the Yoshimura Y-77 slip-on muffler on it. It did pop a little and after about 1000 miles, I guess the system learned and it was perfect.

    I decided to put the factory can back on the bike and now it stalls on idle. Hot or cold, it will NOT idle unless I give a little throttle. Is this due to my ECU needing to re-learn the muffler? I've been using the same Chevron high-octane gas the whole time from basically the same gas station as well since before and after I put the stock can back on.

    I also disconnected the battery for maybe 2 minutes. Maybe I should have left it disconnected long enough to reset the ECU???

    Should I be worried?
  10. slide

    slide A nation with a future

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    I think you are worried or you'd not have posted. Why not let the bike sit with the battery disconnected for longer as an experiment? I don't think you can make things worse.
  11. MFGamesta

    MFGamesta Been here awhile

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    Thanks. My issue is resolved. I did what I was told is the TPS reset (ignition on, wide-open throttle for 5 seconds, release). That worked. Or it just decided to work on my way home from work.

    No issue now.
    goodburbon likes this.
  12. mosey.levy

    mosey.levy Long timer

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    Bought this bike used for my brother a few months ago. Only ran it occasionally. Rode fine.
    2009 F650GS twin. 18k miles.

    As of a few days ago it stalls and sputters.
    When it's first warming up it makes these weird noises. Maybe someone can get an idea of the issue from this video of it warming up?

  13. RedHawk47

    RedHawk47 Adventurer Supporter

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    Probably crud in the fuel injectors.
    Run a dose of injector cleaner thru it.
    Sea Foam, StarTron, or Techron
    Dan
    mosey.levy likes this.
  14. mosey.levy

    mosey.levy Long timer

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    I put a 1/4 bottle of Techron in. DO I need to run through the entire tank to feel the benefits?
  15. bross

    bross Where we riding to? Supporter

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    Yes
  16. Spektrum84

    Spektrum84 Been here awhile

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    If injector clearer works it should be progressively better. I just put techron in the fuel when I do my oil changes.
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  17. JRWooden

    JRWooden Homeless motorcycle vagabond ... and ... loving it

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    I called Techron a while back and asked what the safe maximum rate of usage was for case of bad clogging...
    They said:

    It was safe up to 2 oz/gallon and up to 5 tanks (aka "doses" ) at that rate per oil change.
    mosey.levy likes this.
  18. slide

    slide A nation with a future

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    My issue seems resolved. I had bad engine misses when changing from spirited riding to sedate riding (coming from the mountains into a settled area). Several suggestions here from fuel pump to cam chain. I'd filled up with sketchy fuel 100 miles before the problem surfaced.

    Dealer said if is persists, it's likely a fuel pump but try the BMW brand of Techron first. I did. During the Techron fuel, the bike missed maybe twice when moving from spirited to easy riding. Since then (3 fuel tanks worth) no issues at all. I think there may be some minor surging at constant low throttle opening cruising which I attribute to normal lean fueling map of this age.

    So as of now, I consider the problem solved. Either bad fuel or something else but it's been enough miles now no issues to see this as a persistent issue.
  19. AntonLargiader

    AntonLargiader Long timer

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    Well, maybe it does.

    A customer of mine had stalling issues with his 800 going back a year or so. The bike would usually restart immediately but he did say that it seemed to happen when he rolled off the throttle. I couldn't make complete sense of his description of the events and eventually replaced the control module which improved things a lot but the problem did not go away. A few months ago he was on a weekend trip and it happened again, and although the bike restarted it became a dangerously chronic occurrence as he made his way home especially in towns where he had to stop a lot. I installed a fuel pressure gauge on the bike as a diagnostic aid; we put a bunch of miles on it and never had a problem. Yeah. That's how it goes.

    Last Sunday we went out for a few hundred miles and I rode the 800. An hour or two into the trip, I pulled away from a light and the bike lost power. No fuel pressure. The bike slowed, still in gear, clutch out, and after maybe eight seconds the engine caught again and pressure was back. Later in the ride it happened more frequently, and usually the pressure would jump back to normal and power would return within about ten seconds, but sometimes I would come to a stop on the side of the road and have to crank the bike for some time before the pressure returned. And I began to observe that very regularly, when I closed the throttle and then opened it again, the pressure would start to drop and usually go to zero (stall) but sometimes recover before that happened. There was a very strong correlation.

    The F800 fuel system is dead-end. The controller runs the pump just enough to maintain the correct pressure, and when consumption is low enough (it goes to zero if you close the throttle above some threshold RPM, like 2500) it shuts off completely. This is easy to see on a pressure gauge. When I closed the throttle, the pump shut off (normal behavior) and often did not restart, leading to a stall. In my case it took several seconds for pressure to dissipate because with all of the additional hoses for the pressure gauge I had somewhat of a pressure accumulator. With the stock setup, the pressure drop could be nearly instantaneous.

    A very likely scenario in my mind, at this point, is that the startup load of the pump overstresses the controller and the output driver circuit starts to break down. Eventually that particular bit of electronics cools enough to function again, but not enough to reliably overcome the next pump start event. I could power up a mountain and as long as I kept the throttle on (pump running at faster speeds) I was fine. If I backed off for a corner, or for traffic, I'd see the pressure start to drop and I knew I needed to get to the shoulder again.

    The problem could be just in the pump, or in the BMS, or in the fuel pressure sensor and theoretically give the same symptoms, but I consider those far less likely. I am replacing both the controller and the pump. The controller because it's a logical suspect given the failure of the pump to restart, and the pump because it has likely burnt out its second controller now. The owner is totally uninterested in saving $100~200 on this repair by replacing only one component.
  20. RBMann

    RBMann Been here awhile

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    Four years ago I had to same problem in Colorado and rode home to Seattle. My theory is the as the fuel pump gets warm it tightens up and does a minor seize when it turn off and then restarts as it cools. The longer you run and the lower the fuel is then the warmer the pump gets. At high speed the there is enough demand and power applied to the pump to keep it turning. Ran the freeway all the way home only stopping to get gas. At each off ramp it would die repeatedly until the tank had fresh cool gas in it. New pump solved the problem.
    Moto_Maniac, RedHawk47 and mosey.levy like this.