My F800gs STALLS LIKE ITS RUNNING OUT OF GAS!

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

  1. mosey.levy

    mosey.levy Long timer

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    How much was the new pump. Did you install it yourself? If so how hard was it?
  2. slide

    slide A nation with a future

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    Sounds reasonable to me. The problem as you describe it fits the conditions where mine choked a few times. OTOH, I've duped those conditions lately with no chokes.
  3. RBMann

    RBMann Been here awhile

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    When I bought it 4 years ago I paid $40 US. Cheap enough that I bought two for some silly reason and now I carry the second as a spare. This link is $50 now.

    http://www.fuelpumpfactory.com/CNT-fuel-pump-p/CNT-942-B3.htm?gclid=CLzSoPWB3bgCFYaDQgod70wAsw

    I did it myself and it is not hard. Here is a link to getting inside the tank to the pump.

    http://advrider.com/index.php?threads/f800-f650-gs-fuel-filter-replacement-how-to.1133619/

    Post #11 in this link has part numbers too.

    http://advrider.com/index.php?threads/replacing-fuel-pump-in-bmw-f800gs.964735/#post-23792900
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  4. JRWooden

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

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    Awesome append - thanks!

    There does ( of course :y0! ) seem to be a correlation between pump problems and low fuel levels - full tank pump submerged... then at some level no longer submerged / cooled...

    I'm not sure at what level the pump is no longer cooled by the liquid gasoline in the tank, but I've heard it is about 3-4 bars....
    The older bikes had a fuel pump controller with a plain aluminum heat sink on top,
    there was a redesign at some point and the newer FPCs have a black powder coat.

    Not sure if your customer had the raw aluminum colored heat sink or the newer one ... could you let us know?

    I think your fix is right on target... fix it, fix it good! :clap

    for reference, this company also sells a pump the claim is compatible (I have not bought one so don't know for sure)...

    http://www.highflowfuel.com/i-23899602-new-intank-efi-fuel-pump-bmw-f650gs-twin-2007-2012.html

    Their ad copy at one time said "compatible with E85" which I would take as a plus...
    Now it just says 'Compatible with modern ethanol-infused pump gasoline"
  5. AntonLargiader

    AntonLargiader Long timer

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    The tank was full. We stopped for fuel 100 yards after where it first happened and I put in 0.85 gallons. The bike had a new (one year old) black controller.

    The pump seizing isn't something I had considered, but it's a very credible theory. And it would in turn create a high startup current, which ties into what I was thinking.

    I think the main take-away from my experience that could help people is recognizing that it's very likely that fuel pressure is being lost, rather than the stalling being from some minor idle control problem. If you really want to document the problem, datalog the voltages on either side of the controller along with the fuel pressure. Then you could get a pretty complete picture of what that system is doing. I'd love to, but I have paying work to do... :)
  6. RBMann

    RBMann Been here awhile

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    When mine started stalling you could hear a whine from the controller/tank/pump area. At idle with everything hot enough that the fan was cycling the whine would stop and a couple seconds later the engine would die. At that time I replaced the silver controller with a black one but that did not solve the problem. Since replacing the fuel pump thing have been fine for 25k miles and four years. The whine was also gone after replacing the pump.
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  7. dpm

    dpm Been here awhile

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    you're all aware that the fuel flows through the body of the pump motor? Fuel temp will rise as level decreases, but the pump is always being cooled and lubricated until it's sucking air.

    This is why the filter always looks black when inspected, carbon from the motor brushes is flushed into it.
  8. Reaver

    Reaver How Did I Get Here?

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    Yeah but no.

    There is no return system so the only flow is the fuel being burned passing by, which is low. Too low to really matter. The pump is submersed in fuel which keeps it cool till the level goes below it.
  9. RBMann

    RBMann Been here awhile

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    +1 Reaver
  10. mosey.levy

    mosey.levy Long timer

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    Ugh. Ran two tanks through with Techron. Still no improvement. Going to run a 3rd tank to see if that helps but I'm not counting on it.

    It still stalls a lot until its warm. It makes a funny tsssss noise when idling at start up. The idle is not steady.

    Once riding for a while it still stalls when slowing down. Even while riding. Scary as it locked up the back tire the other day at around 10mph

    Any ideas what to try next?





    Side note: a few weeks ago before the problem started, the bike fell over while parked in the grass over night due to rain and me not putting anything under the kick stand. Was like that for a few hours I can assume. I started it up then and ran it for 10 minutes and it seemed fine. But maybe it's related?
  11. bross

    bross Where we riding to? Supporter

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    Have you got a charcoal canister? If so, it could be flooded and causing your issues.
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  12. mosey.levy

    mosey.levy Long timer

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    I have no idea. What am I looking for?
    I'll have to google it. Thanks.
  13. ebrabaek

    ebrabaek Long timer

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    Look for a black colored can about the size of a beer in the inside of the regulator rectifier. There have been a few cases on previous 2010 models before the recall where the y pipe was inserted, where the bike stalled. Some prognosis was rider over filled the tank and excess or expanded fuel made it into the canister and over time disowned the charcoal and then when the purge valve opened to combust the fumes dissolved charcoal was sucked into the manifold......not through the fuel system.
    My take is that the bikes died due to a rich running as the purge valve opened, and that is not what you have going.
    Now back on the other side before Loutre shows......:-)
  14. jallenb

    jallenb taking the backroads

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    I just recently fixed the stalling issue on my '10 F800GS with 15k miles with a new BMW OEM fuel pump. After "fixing" this issue last year with a Chinese pump for a Toyota Corolla, I found the non-BMW pump to be a subpar short-term solution.

    The issue started with a loss of power, no stalling, in the 3000-3500 RPM range and it wasn't noticeable in 1st or 2nd gear. It was a real problem accelerating on hill climbs. As a crutch, I got used to going down a gear to keep RPMs high while I was trying to figure out what was going on. Then it began stalling in the 2000-3000 RPM range about 1000 miles afterward. And it only stalled after the bike warmed up from cold. :hmmmmmThis was a super annoyance and it had me looking at the KTM 690 Enduro R.

    I feel like the bike experienced every symptom on this thread. Prior to installing the Chinese pump last year, the bike stalled on hot days when the tank was low which makes sense as gasoline will cool the normally submerged pump. That pump lasted about 2000 miles before the power loss issue started. Unfortunately, I still thought the pump was ok (since it wasn't that old), so instead of replacing it I tried a new throttle positioning sensor and idle control device; both of which showed no improvement.

    It's bad fuel. The bike is 6 years old with 15k miles, which has me riding about 2500 mi. per year. This just is not enough riding to keep the fuel fresh. Fix your fuel pump (yes, you can do it yourself) and buy a large bottle of your favorite fuel stabilizer.

    I love this bike. It's the right size and fit for me and my style of riding. I don't want to fuss with 6000 mi valve checks on the Austrian anyway. :rofl
  15. Effisland

    Effisland Long timer

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    the funny sound you describe on idling sounds like one of the spark plugs might be loose and there is blowback. Maybe some water got in there when you left the bike on the side.

    edit: By the way I suggest this because I think this problem sounds similar to what happened to mine last year that damaged one of my stick coils. I checked the plugs, one seemed like it might not have been not torqued all the way and I put in a new one just in case (though it looked ok, though a bit blackened). A slight amount of rust on the white insulation should have also been a clue to the real issue (water getting in there). The second thing I suspected after plugs was the coil however I couldn't find a way to test it - got a shop to test it and they couldn't find an issue - I now know this was because they also didn't know how to test it.

    However back then I didn't suspect the coil and removed and cleaned the fuel pump, injectors, etc. With a cold engine on idle check the exhaust pipes and see if they both heat up the same. If one stays cold it's the coil (or plug). Or, perhaps, gas not getting in there, but you'd have one funky plugged fuel line (or injector) to cause this. Doubtful given what you described.
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  16. mosey.levy

    mosey.levy Long timer

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    So we removed the charcoal canister today. No improvement. The good news though is after doing that we found a broken hose that I believe has to do with air and gas mixture. I'm not sure exactly what it is, and I can't get to it easily without removing entire "intake sound system".

    I took a few photos.
    [​IMG][​IMG][​IMG][​IMG]
  17. sarathmenon

    sarathmenon Armchair Adventurer

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    It's not clear to me from the photos, but that looks like the breather hose. If it's the case, yeah I can see why your bike is running like crap. Did you follow all the instructions from the canisterectomy pictorial? There is a hose that goes into the canister from the throttle body which is also in that general location.
  18. mosey.levy

    mosey.levy Long timer

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    I got the airbox off today. There is a little T at the bottom with three hoses coming off it. One of them is the broken one. Looks like to get it like new I would need an entirely new airbox. Found one for sale on ebay for $50 but it's weeks away and I have a trip in 3 weeks.

    Here's a couple photos I pulled from the listing. See the part circled in red. That's what's cracked off.

    Maybe I can use vacuum connectors to repair it and some new hose line.
    [​IMG][​IMG]
  19. mosey.levy

    mosey.levy Long timer

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    [​IMG][​IMG]

    Using some JB Weld to keep some vacuum connectors in place to get the hoses back on. At least until I can get a replacement air box.

    Ignore the hose in the photo it's just holding up one of the connectors while it dries.
  20. shuswap1

    shuswap1 Long timer

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    Goop glue is your friend here also, apply it from a fresh tube, quickly and much thicker than you think makes sense(it shrinks as it cures)
    I have used it for more than 15 years with outstanding success....it sticks to EVERYTHING that is clean and you can add layers if necessary.

    Downside: smelly and its kinda slow cure rate..... but it gets stronger every day.....over several months, perhaps even years.

    Personally, done right, it would negate the purchase of a replacement airbox, at least for me.

    PS: That looks to be your issue
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