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Discussion Starter #1
I did a search and read parts of many posts and the common thread seems to be a gauge that reads too low and or a warning light that doesn't work right.
I started my bike today and the gauge read full. It never dawned on me that it should be almost empty from my last ride. Sure enough, on the way to work I ran out of gas. I got help and added a gallon and the gauge still reads full. The bike is a 2000. Any ideas where to look?
 

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I am probably not going to be the only one to ask this but do you still have your charcoal canister connected? Does air rush in when you open the gas cap? If you do on either, then likely, the purge system is clogged ( canister ) and that ends up putting vacuum on the fuel tank as fuel is removed. This causes the sides of the tank to cave in and if it goes far enough, it crushes the sending tube and doesn't allow the float to move. Normally it is stuck low but it is worth a look to see if there is damage to it. It can be taken apart and made round again so the float moves freely. In any case, it is likely the sending tube unless you have a shorted wire which is also possible.
 

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My 2005 R1200RT came with a full tank of fuel, or so I foolishly thought. Same issue, read full all the time. Had the sender strip replaced and now all is good. I do use the trip odometer as a backup now though.
 

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2005 K1200LT
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Yup. Fuel sender has a ding in it. Easy to do if you stick the fuel nozzle too far into the tank. It is a thin tube with a float in it. Pull tupperware on the right side and undo the 6 bolts. Then disassemble the unit (nut at the bottom under spring) slide the tube off and remove the dent. Reassemble and check for smooth movement of the float.
 

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My 2005 R1200RT came with a full tank of fuel, or so I foolishly thought. Same issue, read full all the time. Had the sender strip replaced and now all is good. I do use the trip odometer as a backup now though.
Those RT fuel strips were awful. Different system on the LT.
 

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Discussion Starter #6
I am probably not going to be the only one to ask this but do you still have your charcoal canister connected? Does air rush in when you open the gas cap? If you do on either, then likely, the purge system is clogged ( canister ) and that ends up putting vacuum on the fuel tank as fuel is removed.
Cannisterectomy was done before I purchased the bike. No air rushing in when cap is removed.
 

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Discussion Starter #7
Yup. Fuel sender has a ding in it. Easy to do if you stick the fuel nozzle too far into the tank. It is a thin tube with a float in it. Pull tupperware on the right side and undo the 6 bolts. Then disassemble the unit (nut at the bottom under spring) slide the tube off and remove the dent. Reassemble and check for smooth movement of the float.
I have considered this and will check it out. The puzzle is the bike was low on fuel when parked and gauge and low fuel light worked well. Next time bike is ridden the gauge pegs at full. I just finished the center stand retrofit and the only electrical disturbed was momentarily disconnecting each side of the battery as I added the two new wires.

Does the gauge move to full with low ohms or high ohms?
 

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2005 K1200LT
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Could be that the connector came off the sending unit. Not sure what it does when disconnected, never tried that out. Nothing near the battery would have caused an issue. One side is ground and the other is split between the low fuel module and the fuel gauge. I just checked my spare sender, 6 ohms when full and 78 ohms when empty. Not much help.
 

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Could be that the connector came off the sending unit. Not sure what it does when disconnected, never tried that out. Nothing near the battery would have caused an issue. One side is ground and the other is split between the low fuel module and the fuel gauge. I just checked my spare sender, 6 ohms when full and 78 ohms when empty. Not much help.
JOHN,

if connector to fuel level sender is unplugged, the fuel gauge will indicate below zero, but the fuel warning light will NOT be on.

The above test was done on 1st gen K1200LT with the old dash design (1999-2004 in USA), so I am NOT sure if 2nd generation will behave the same.
 

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2005 K1200LT
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Thanks John that helps. His is suddenly showing full. New failure mode! Maybe the wires got pinched and finally wore through to a short.
 

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Discussion Starter #11
With the sender disconnected the gauge reads full. The sender reads 10.2 ohms which should indicate not quite full. I will try to trace the wires to look for a short. Can anyone tell me where the fuel level control is located so I have an idea where the wires are headed from the sender?
Any other ideas?
 

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With the sender disconnected the gauge reads full. The sender reads 10.2 ohms which should indicate not quite full. I will try to trace the wires to look for a short. Can anyone tell me where the fuel level control is located so I have an idea where the wires are headed from the sender?
Any other ideas?
According to the schematic, the gauge is directly connected to the sending unit. Looks like a yellow wire with a brown stripe. It has a T off to the fuel warning light control unit. That is a relay looking thing mounted with the other relays under the tank according to the Clymer.
 

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Discussion Starter #13
Thanks. I will look at my schematic closer. I thought it went to the control unit and the to the gauge. I guess I need to pull it all apart again. I will follow up when I find the answer.
 

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Re: Fuel gauge too high - SOLVED

Thanks to you all. After understand the OHM readings (about 6 OHMS full and 75 empty) I decided to dig into it to verify that the gauge itself was not the culprit I disassembled lots of parts until I could access the rear of the gauge panel. I removed the 3 wires from the back of the fuel gauge. I used a spare battery and test leads with alligator clips and wired the gauge to the sender completely bypassing the onboard wiring.
The gauged worked correctly.
I tried to follow the wiring from the sender and found nothing obvious. I dug deeper and noticed the chaffing on the harness wrapping where the wires from the sender passed over the top of the tank and under the frame that goes over the tank and supports the seat hinge. I cut open the wrapping and found the yellow and violet ( I think) wire had a very tiny hole rubbed in it that could short against the frame. That was properly soldered, insulated and re-routed and voila!!!
The problem is fixed.

Thanks to all who helped point me in the right direction. No tomorrow I just have to re-assemble.

I LOVE THIS FORUM!
 

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Re: Fuel gauge too high - SOLVED

Thanks to you all. After understand the OHM readings (about 6 OHMS full and 75 empty) I decided to dig into it to verify that the gauge itself was not the culprit I disassembled lots of parts until I could access the rear of the gauge panel. I removed the 3 wires from the back of the fuel gauge. I used a spare battery and test leads with alligator clips and wired the gauge to the sender completely bypassing the onboard wiring.
The gauged worked correctly.
I tried to follow the wiring from the sender and found nothing obvious. I dug deeper and noticed the chaffing on the harness wrapping where the wires from the sender passed over the top of the tank and under the frame that goes over the tank and supports the seat hinge. I cut open the wrapping and found the yellow and violet ( I think) wire had a very tiny hole rubbed in it that could short against the frame. That was properly soldered, insulated and re-routed and voila!!!
The problem is fixed.

Thanks to all who helped point me in the right direction. No tomorrow I just have to re-assemble.

I LOVE THIS FORUM!
Last time I had her undressed, I took the time to re-wrap a lot of my harness where the insulation had deteriorated leaving nothing but a bundle of wires in some spots. It seemed prudent as I have heard many stories on these aging bikes of just that type of thing. Glad it is fixed.
 

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Re: Fuel gauge too high - SOLVED

Last time I had her undressed, I took the time to re-wrap a lot of my harness where the insulation had deteriorated leaving nothing but a bundle of wires in some spots. It seemed prudent as I have heard many stories on these aging bikes of just that type of thing. Glad it is fixed.
What did you wrap your wiring with?
 

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Re: Fuel gauge too high - SOLVED

What did you wrap your wiring with?
Plastic electrical tape is unreliable in the long run. I used cloth friction tape.
 

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Re: Fuel gauge too high - SOLVED

Plastic electrical tape is unreliable in the long run. I used cloth friction tape.
That was my thought on the electrical tape, which is why I asked. I know the harnesses on my bike are starting to crumble from age, and I really need to rewrap them. Good choice on the friction tape. I hadn't thought of that.
 
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