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Thread: Erratic Fuel level Indicator

  1. #1
    Extra pieces? geobeemer's Avatar
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    Erratic Fuel level Indicator

    2001 R1150GS - The Fuel level indicator was acting up last fall and yesterday the fuel level dropped to nothing with only 148 miles on the tank. No low level light came on yet so it would seem that the light and the fuel level are 2 different sensors. I have never replaced the fuel filter or had the tank open for anything other than to put gas in it. At times last year when I knew my fuel was low the LCD screen would indicate full and then drop down. As I mentioned, erratic behavior appears to be the norm now.

    Since I should probably go in and replace the fuel filter is there something else in the tank that I should be looking for or parts that I should order before I even start?
    2000 K1200LT
    2001 R1150GS
    2009 KLR650

  2. #2
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    I heard that the ethanol gas will react with the fuel lever sender strip.

  3. #3
    Unregistered user norton's Avatar
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    When you are in the gas tank please take the time to renew all the rubber fuel hoses with the appropriate submersible fuel line. There are 3 hoses to replace, 2, 2" straight lengths, and 1, U shaped hose. Pick up the oetiker fuel line clamps too.

    You can get most of what you need at http://www.beemerboneyard.com/r81111r1fupu.html

    As to your fuel gauge being erratic, check the vent lines from the tank and make sure that they are in good order. If you have some pressure build up in the in the tank when you open the fuel cap, it would indicate that the carbon canister is plugged. The fuel gauge is driven from a float located in the tube inside the tank. The low fuel light is driven by the float arm that is located in the fuel filter assembly. There are 2 electrical plugs associated with the tank. One inside that controls the the low fuel light, and the large plug on the right underside of the tank. Make sure that the large plug is clean and securely plugged in.

  4. #4
    Extra pieces? geobeemer's Avatar
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    I have checked the vacuum and it seems ok. No change to the guage either once tank opened up or even a rush of air. Thank you for the link. It sounds like I should just order the whole kit while I am in there. I will check the external connector this evening. Thanks guys!
    2000 K1200LT
    2001 R1150GS
    2009 KLR650

  5. #5
    Day Dreaming ... happy wanderer's Avatar
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    Quote Originally Posted by norton View Post
    When you are in the gas tank please take the time to renew all the rubber fuel hoses with the appropriate submersible fuel line. There are 3 hoses to replace, 2, 2" straight lengths, and 1, U shaped hose. Pick up the oetiker fuel line clamps too.

    You can get most of what you need at http://www.beemerboneyard.com/r81111r1fupu.html

    As to your fuel gauge being erratic, check the vent lines from the tank and make sure that they are in good order. If you have some pressure build up in the in the tank when you open the fuel cap, it would indicate that the carbon canister is plugged. The fuel gauge is driven from a float located in the tube inside the tank. The low fuel light is driven by the float arm that is located in the fuel filter assembly. There are 2 electrical plugs associated with the tank. One inside that controls the the low fuel light, and the large plug on the right underside of the tank. Make sure that the large plug is clean and securely plugged in.
    They still don't have a replacement for the 180 degree pump to filter hose. Wish they did! The price for that short piece of rubber hose at the dealer is $35.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  6. #6
    Unregistered user norton's Avatar
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    There is an aftermarket U fuel line. It's a little longer, after you cut it to length, but it works fine.

    http://www.euromotoelectrics.com/BMW...fp-hosekit.htm

  7. #7
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    erratic fuel level indicator - hah!

    I got this.
    I have a 1998 1100 RT, and every so often this comes back around, usually in combination with rough idle or whatever.
    I have a theory that sulfur compounds added more prevalently to modern gasoline leaves a non-conductive coating on the sender.
    Dump in a whole bottle of STP Fuel System Cleaner and then fill the tank with fuel. I know it says "up to 20 gallons" but it'll be fine.
    The cleaner has detergents that dissolve the sulfur compounds.

  8. #8
    Pepperfool GSAddict's Avatar
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    Quote Originally Posted by scott.lambert View Post
    I got this.
    I have a 1998 1100 RT, and every so often this comes back around, usually in combination with rough idle or whatever.
    I have a theory that sulfur compounds added more prevalently to modern gasoline leaves a non-conductive coating on the sender.
    Dump in a whole bottle of STP Fuel System Cleaner and then fill the tank with fuel. I know it says "up to 20 gallons" but it'll be fine.
    The cleaner has detergents that dissolve the sulfur compounds.
    You are right about the sulfur IMO. I clean my sender board every filter change, (sometimes more) with a Q tip and electrical contact cleaner.
    Pain in the ass. I can't stand stuff that does not work correctly.
    Other brands of vehicles in this area have reported similar problems and the word sulfur comes up in discussions.
    I will try a bottle of STP next time to see if it works.
    FYI sender resistance should read as follows:
    Full: 3.5 ohms or less
    Empty: 80 ohms
    '
    Ufda happens..........

    It's all about the details.

  9. #9
    Extra pieces? geobeemer's Avatar
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    I checked the connector and it seems fine, no corrosion and wires look healthy. Looks like the next step is STP and if that doesn't help then it is time to take things apart.
    2000 K1200LT
    2001 R1150GS
    2009 KLR650

  10. #10
    Day Dreaming ... happy wanderer's Avatar
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    Quote Originally Posted by norton View Post
    There is an aftermarket U fuel line. It's a little longer, after you cut it to length, but it works fine.

    http://www.euromotoelectrics.com/BMW...fp-hosekit.htm
    Yeah I have one of those hoses but the last time I changed my filter the radius of the 180 bend was so much larger than the original rubber hose I was worried it might not fit in there or interfere with something. Have you installed one?
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  11. #11
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    Mr. Glaves?

    I have to assume that the erratic gauge was fixed at some point in history.
    Is the sender a different design nowadays?
    Did they gold-plate the contacts on later models or something?
    I'm wondering if there is some sort of mod or upgrade possible.

  12. #12
    Scottish Transplant Picinisco's Avatar
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    I clean my sender board every filter change, (sometimes more) with a Q tip and electrical contact cleaner.
    Alternative, and a tip that was passed on to me, is to clean the contact on the half moon sender board with the eraser on the end of a pencil. Works great and actually helps the sender to read "more correctly" the fuel in the tank.
    2004 R1150GS 1978 R75G/S Frankenbike
    AMA - BMWMOA - BMWRSOC - AZBEEMERS
    Gilbert, Arizona

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