fuel sender

[Bish]

Hi , could anybody advise me on how to test a fuel sender on a XS1100SF , in my manual it goes on about a floating gauge but , having removed it it is not a floating level gauge . Many thanks Clive (bish).

[jwhughes3]

Unsure as to test procedure but its likely increasing Ohms over its range.

CaptonZap probably knows.

It should have an arm and a float at the end. All similar except standards are oriented backwards from specials.

John

[bikerphil]

The Specials use a thermistor, a thermal resistor. When it is submerged in liquid, the gauge light remains off, when out of the liquid, the light should go on. I have had them go bad before. My test was to try another in it's place.

[jrobertfox]

Perhaps a little late, in the manual it says it should read 1500 +/- 100 Ohms at 77F ambient temp with the tank empty.

I wonder what it reads with the tank full...

[fredintoon]

Hi , could anybody advise me on how to test a fuel sender on a XS1100SF , in my manual it goes on about a floating gauge but , having removed it it is not a floating level gauge . Many thanks Clive (bish).

Hi Clive,
your manual is talking about the Standard's rheostat sender.
Your Special has a thermistor sender.
jrobertfox's post just above yours tells you all about it.

[jetmechmarty]

Perhaps a little late, in the manual it says it should read 1500 +/- 100 Ohms at 77F ambient temp with the tank empty.

I wonder what it reads with the tank full...

Without looking at the schematic, I would expect the circuit to be open.

[fredintoon]

Without looking at the schematic, I would expect the circuit to be open.

Hi Marty,
not quite. I forget the number but I had to use the multimeter's MegaOhm range to get a reading.
What happens is the very small current always tries to heat the thermistor.
When the thermistor is under the gas the heat gets sucked away.
When the thermistor dries up it's bulb gets warmer which lessens the resistance which lets the current flow enough to light up the warning light.

[jetmechmarty]

Thank you for clearing that up, Fred!