Page 1 of 2 1 2 LastLast
Results 1 to 15 of 24

Thread: fuel sender and damping unit

  1. #1
    aapasquale
    Join Date
    Aug 2011
    Location
    Sag Harbor, New York
    Posts
    145

    fuel sender and damping unit

    my fuel level light has been on all the time for a few months--today I removed the fuel pump/level sender from the tank--four wires: brown, green, yellow white (in order)--I'm trying to figure out which is the fuel sender wire--am I correct in assuming brown is ground?--

    couple more questions:
    --is it okay to turn key to on(not to start position) without the tank/fuel pump/sender unit connected? I want to see if level light on dashboard is on or off when sender is disconnected
    --in the wiring schematics there is a damping unit--where is it located on the bike?
    --is it possible for this damping unit to fail? if it does, how does this failure present itself?

    As you can see, I'm quite new at this, so please forgive my ignorance--
    thanks for any help in solving this puzzle
    Tony

  2. #2
    Registered User rxcrider's Avatar
    Join Date
    Aug 2010
    Location
    North Ridgeville OH
    Posts
    715
    First off, giving us the year and model usually helps; in the title is ideal.

    The description you are giving sounds like what I'm seeing in the diagram for my 1995 R1100RS. It looks like the damping unit controls the low fuel light, probably keeping it from flickering, maybe reducing the voltage at the switch in the tank - not sure - just guessing. The brown wire should be ground and the white wire should control the low fuel light from what I'm seeing. I think you are on the right path with turning the key on with the sending unit unplugged, but I'm not sure when the switch should be open or closed with regards to operating the light. If you need some resistance measurements taken, I can pull out my spare sending unit in the next day or two and get them for you. Good Luck - Jonathan

  3. #3
    Pepperfool GSAddict's Avatar
    Join Date
    Feb 2008
    Location
    Sechelt, British Columbia
    Posts
    1,368
    my fuel level light has been on all the time for a few months--today I removed the fuel pump/level sender from the tank--four wires: brown, green, yellow white (in order)--I'm trying to figure out which is the fuel sender wire--am I correct in assuming brown is ground?--Brown is Ground

    couple more questions:
    --is it okay to turn key to on(not to start position) without the tank/fuel pump/sender unit connected? I want to see if level light on dashboard is on or off when sender is disconnected Yes
    --in the wiring schematics there is a damping unit--where is it located on the bike? In the fuse box
    --is it possible for this damping unit to fail? if it does, how does this failure present itself? Rare I have never seen one fail


    Low fuel lamp lights when the float arm drops low enough to close the circuit on one side of the sender board, the damper relay stops nuisance flashing of the light due to sloshing fuel.
    Fuel level damping is done internally in the RID display unit.
    Level switch is on or off. Brown to White
    Sender board resistance range is approx. 2 ohms (full tank) to approx 85 ohms (empty tank) Brown to Yellow
    Be sure to carefully clean the sender board with a Qtip soaked in electrical contact cleaner, deposits from fuel will affect fuel gauge readings eventually causing it to read low.
    '
    Ufda happens..........

    It's all about the details.

  4. #4
    Registered User rxcrider's Avatar
    Join Date
    Aug 2010
    Location
    North Ridgeville OH
    Posts
    715
    GSAddict - thanks for the good info - hopefully it gets Tony headed in the right direction.

  5. #5
    aapasquale
    Join Date
    Aug 2011
    Location
    Sag Harbor, New York
    Posts
    145

    mea culpa

    Quote Originally Posted by rxcrider View Post
    First off, giving us the year and model usually helps; in the title is ideal.

    The description you are giving sounds like what I'm seeing in the diagram for my 1995 R1100RS. It looks like the damping unit controls the low fuel light, probably keeping it from flickering, maybe reducing the voltage at the switch in the tank - not sure - just guessing. The brown wire should be ground and the white wire should control the low fuel light from what I'm seeing. I think you are on the right path with turning the key on with the sending unit unplugged, but I'm not sure when the switch should be open or closed with regards to operating the light. If you need some resistance measurements taken, I can pull out my spare sending unit in the next day or two and get them for you. Good Luck - Jonathan
    Sorry! It is a 1994 BMW R1100RS
    Tony

  6. #6
    aapasquale
    Join Date
    Aug 2011
    Location
    Sag Harbor, New York
    Posts
    145
    Quote Originally Posted by GSAddict View Post
    my fuel level light has been on all the time for a few months--today I removed the fuel pump/level sender from the tank--four wires: brown, green, yellow white (in order)--I'm trying to figure out which is the fuel sender wire--am I correct in assuming brown is ground?--Brown is Ground

    couple more questions:
    --is it okay to turn key to on(not to start position) without the tank/fuel pump/sender unit connected? I want to see if level light on dashboard is on or off when sender is disconnected Yes
    --in the wiring schematics there is a damping unit--where is it located on the bike? In the fuse box
    --is it possible for this damping unit to fail? if it does, how does this failure present itself? Rare I have never seen one fail


    Low fuel lamp lights when the float arm drops low enough to close the circuit on one side of the sender board, the damper relay stops nuisance flashing of the light due to sloshing fuel.
    Fuel level damping is done internally in the RID display unit.
    Level switch is on or off. Brown to White
    Sender board resistance range is approx. 2 ohms (full tank) to approx 85 ohms (empty tank) Brown to Yellow
    Be sure to carefully clean the sender board with a Qtip soaked in electrical contact cleaner, deposits from fuel will affect fuel gauge readings eventually causing it to read low.
    Thanks! My bike doesn't have RID, just the light for low fuel--either on or off-- Have examined the fuel level sender board and it looks very clean

  7. #7
    aapasquale
    Join Date
    Aug 2011
    Location
    Sag Harbor, New York
    Posts
    145

    checked out sender

    Quote Originally Posted by GSAddict View Post
    my fuel level light has been on all the time for a few months--today I removed the fuel pump/level sender from the tank--four wires: brown, green, yellow white (in order)--I'm trying to figure out which is the fuel sender wire--am I correct in assuming brown is ground?--Brown is Ground

    couple more questions:
    --is it okay to turn key to on(not to start position) without the tank/fuel pump/sender unit connected? I want to see if level light on dashboard is on or off when sender is disconnected Yes
    --in the wiring schematics there is a damping unit--where is it located on the bike? In the fuse box
    --is it possible for this damping unit to fail? if it does, how does this failure present itself? Rare I have never seen one fail


    Low fuel lamp lights when the float arm drops low enough to close the circuit on one side of the sender board, the damper relay stops nuisance flashing of the light due to sloshing fuel.
    Fuel level damping is done internally in the RID display unit.
    Level switch is on or off. Brown to White
    Sender board resistance range is approx. 2 ohms (full tank) to approx 85 ohms (empty tank) Brown to Yellow
    Be sure to carefully clean the sender board with a Qtip soaked in electrical contact cleaner, deposits from fuel will affect fuel gauge readings eventually causing it to read low.
    Checked the sender with multimeter--as far as I can tell, rheostat and switch are working properly --I will check the relay for the damper and then check out the wiring to light panel--

  8. #8
    Pepperfool GSAddict's Avatar
    Join Date
    Feb 2008
    Location
    Sechelt, British Columbia
    Posts
    1,368
    I have a Damper relay if you happen to need one.
    '
    Ufda happens..........

    It's all about the details.

  9. #9
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,035
    Quote Originally Posted by GSAddict View Post
    Be sure to carefully clean the sender board with a Qtip soaked in electrical contact cleaner, deposits from fuel will affect fuel gauge readings eventually causing it to read low.
    Wait a sec... this give the impression that the sender board is used for fuel gauge indication but the sender board is only used for the low fuel light. It is one of two components in the tank. The other is the long tube with a float in it that is used for the fuel gauge indication on the RID.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  10. #10
    Registered User rxcrider's Avatar
    Join Date
    Aug 2010
    Location
    North Ridgeville OH
    Posts
    715
    Quote Originally Posted by Happy Wanderer View Post
    Wait a sec... this give the impression that the sender board is used for fuel gauge indication but the sender board is only used for the low fuel light. It is one of two components in the tank. The other is the long tube with a float in it that is used for the fuel gauge indication on the RID.
    That isn't the case for all oilheads. The RS does everything from the float arm and sender board. In the case of this 1994, it doesn't have a RID and only runs the low fuel light.

  11. #11
    Day Dreaming ... happy wanderer's Avatar
    Join Date
    Mar 2010
    Location
    Vancouver, B.C. Canada
    Posts
    2,035
    Quote Originally Posted by rxcrider View Post
    That isn't the case for all oilheads. The RS does everything from the float arm and sender board. In the case of this 1994, it doesn't have a RID and only runs the low fuel light.
    Does the RS have a fuel gauge of any kind or just a low fuel light? I really don't know.

    I do know first hand that for the bikes that do have a fuel gauge display (RID) which the GS and RT do, there is a separate device in the tank for the gauge and the float arm is only for the low fuel light. I was trying to clarify that. Sorry for any confusion there.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  12. #12
    Registered User rxcrider's Avatar
    Join Date
    Aug 2010
    Location
    North Ridgeville OH
    Posts
    715
    As far as I can tell, the RS bikes built prior to Novemmber 1993 only had a low fuel light. The ones built after that got the RID as well.

  13. #13
    aapasquale
    Join Date
    Aug 2011
    Location
    Sag Harbor, New York
    Posts
    145

    update

    Quote Originally Posted by GSAddict View Post
    I have a Damper relay if you happen to need one.
    Hi all--
    found the damper relay in the #2 position in fusebox--when key is turned on, light is on--pull the relay and light goes out--went one step farther and connected the sender unit to bike (not the fuel pump!)--no change to light when arm was up or down--I checked as much of the wiring as I could without taking it all apart--no change--I think the next is to see if I can borrow GSAddict's relay before I purchase another--Is there any way to test this relay?
    Tony

  14. #14
    Registered User rxcrider's Avatar
    Join Date
    Aug 2010
    Location
    North Ridgeville OH
    Posts
    715
    Have a multimeter or test light and a jumper?

    With the relay unplugged, you should NOT have continuity between the terminal (on the relay) where the white / green wire connects and the terminal (on the relay) where the brown wire connects. If you can't see the wires, maybe GSAddict can provide details again. If not, I can pull my spare harness and relay box to figure out what you need to probe.

  15. #15
    Pepperfool GSAddict's Avatar
    Join Date
    Feb 2008
    Location
    Sechelt, British Columbia
    Posts
    1,368
    Quote Originally Posted by Happy Wanderer View Post
    Wait a sec... this give the impression that the sender board is used for fuel gauge indication but the sender board is only used for the low fuel light. It is one of two components in the tank. The other is the long tube with a float in it that is used for the fuel gauge indication on the RID.
    RT's are different.
    '
    Ufda happens..........

    It's all about the details.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •