Reply With QuoteNot sure if you can without pulling the pump. But, if you're going that route, then I would order new filters and o-rings for the sake of it.
Hey guys, had an incident yesterday where my low fuel light and trip meter did not come on even though I only had about 0.15 gallons left in the tank. I did a bit of Googling but I couldn't find a way to test the switch/sensor without first pulling the fuel pump. If I have to pull it I am perfectly capable of such task but if I can test it first that would be ideal. Thanks
Bike is a 2009 XB12R
Not sure if you can without pulling the pump. But, if you're going that route, then I would order new filters and o-rings for the sake of it.
neil: there is no known test. the sensor has the appearance of a condensor for a car/cycle points type ignition system. everyone i've ever seen has a yellow/red tracer wire from same. it is possible for that wife to "chafe". no tests but here are the known symptoms:
1-low fuel light in conjunction with mileage counter constantly activated.......cause:chafed LFS wire.
2-failure of low fuel light/mileage counter to function.............cause: failed LFS.
easy to replace. tons of "how to remove/replace fuel pump" threads on here.
i have the LFS part # along with O-ring part # if you need them neil. still plenty in the dealer pipeline. also closely check the pump wiring loom for chafed pump assembly wires. many are and need to be addressed properly when discovered.
Last edited by user_deleted; 04-05-2017 at 11:48 AM.
Yeah John, I would very much appreciate the part numbers if you have them readily available, otherwise I can just do a bit of thread surfing to get them.Originally Posted by lunaticfringe
Hey John, do you carry these parts ?
Last edited by njloco; 04-05-2017 at 12:50 PM.
I connected my low fuel sensor wire to relay to make it works with LED on Motogadget instrument cluster, now low fuel light comes slightly earlier than it was before with stock XB instrument cluster. I believe this sensor is just thermistor, so if you want to test it you need to measure resistance of the low fuel sensor circuit with full tank, then pump the fuel out the tank and measure resistance again (in both cases engine should work while measuring resistance). Then you need to compare the measured resistances with healthy low fuel sensor resistances. If the resistance is OK the problem is in the circuit of the instrument cluster. If the resistance if wrong the problem likely is in the low fuel censor circuit. To locate the low fuel sensor wire check your motorcycle electric manual.
If you are very desperate about fixing low fuel sensor issue as fast as possible you can try to solder potentiometer in line of the low fuel sensor circuit and adjust the circuit resistance (increase it) to compensate the malfunction and adjust low fuel level you need. But this might not work well if the resistance of the low fuel sensor circuit is floating.
Last edited by TPEHAK; 04-05-2017 at 02:45 PM.
Thanks for the very detailed description on how to test the sensor. I think the only issue would be finding out the resistance on the healthy LFS to compare my findings to.
Also not desperate to have a low fuel light as I generally go by the trip meter, I just like to know that my bike works as it should.
According to the factory service book, the wire that drives the lamp is Y/R (which I assume is yellow/red) and goes from terminal A at the fuel pump to terminal 15 at the cluster.
I'd first pull the cluster and verify the bulb and connection is good.
Then I'd verify my findings of the wire color and terminal locations and do a continuity test between the two endpoints of the wire.
Looking at the diagram, it looks like the sensor at the pump just provides a path to ground, so it would assume that the wire should have a positive current passing through it. If the wire shows current (I assume 12v?) passing though it to the fuel connector end, you will probably need to pull the pump and follow Johns instructions. Like he said, you may find a chafed wire or may need to replace the sensor. As I understand it, Buell only sold the fuel pump as a complete assembly, so that sensor may or may not be available separately.
Here is something to consider. On my new Sportster Roadster, I installed a new fuel level sensor so I could actually have a gauge (built into the speedo) rather than just a low fuel light.
In the instructions, it pointed out...
Look at the gap between the fuel hose and the sensor. The gap must be at least 1.5 mm (0.06 in). If gap is too small or there is contact between fuel hose and fuel sensor, rotate fuel filter approximately 3.3 mm (0.13 in) to move fuel hose away from fuel sensor. If gap is still too small, remove fuel sensor and bend mounting tab slightly away from fuel hose until gap is sufficient.
c.
Look at the gap between the fuel sensor and fuel pump wiring. The gap must be at least 1.5 mm (0.06 in). If necessary, move wiring with a blunt tool, such as a screwdriver.
Like I mentioned about, I think Buell only sold the pump as part of a complete fuel pump assembly for some serious $$$. People realized that the pump is cross compatible with a Ford (Mustang?) pump and have been retrofitting that when the original fails. Perhaps this was done in the past, and the wire scenario above exists.
If the connection is bad in the low fuel sensor circuit the low fuel light should comes earlier because of resistance of the circuit will be higher. Later low fuel light means the low fuel sensor circuit does not have enough resistance.
neil: 2 pump O-rings required. factory part # is P0125.02A8.....also available same # with A suffix. they are one and the same part. retail about $6.50
damn near impossbile to locate the fuel sensor part # via dealer computer system or other sources BUT the correct part # is
P0789.K retail about $15
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