wiring problem with fuel gauge

[rscbao]

Present State of Affairs

After hooking everything back up, with a supposedly good sending unit, good gauge, and new by-pass y/b and b/w wires as well as connectors (posi locks), the fuel gauge is now stuck between the red and white areas. There is no movement at all. Do any of you hard-core, do-it-until-it-works, types have any further suggestions.

I would sure like this thing to work before I quit.:-D :-D :-D

[tfb]

OK, it's time we asked, what sort of mechanism are we talking about inside the fuel gauge?

If it's anything like the temp. gauge in my old GS1000S, that was a bimetallic strip with a heating coil wrapped arount it.

Do our fuel gauges operate on the same principle? If so, then maybe there's something up with the coil around the bimetallic strip?

Whatever, it still sounds like a right-proper mystery... but I'm trying to come up with a fresh angle that may help yield a solution -- even incidentally! :?

[Pharkmeh]

my fuel gauge is called an odometer....:shock:

200km's - better fill it or walk it...

[Metal Jim]

Fuel level indicator

The bike is equipped with an alternate fuel level indicator: the petcock.

[rustybronco]

OK, it's time we asked, what sort of mechanism are we talking about inside the fuel gauge

it's an ammeter it measures current flow

If it's anything like the temp. gauge in my old GS1000S, that was a bimetallic strip with a heating coil wrapped arount it.?

Do our fuel gauges operate on the same principle? If so, then maybe there's something up with the coil around the bimetallic strip?

i have never taken a fuel gauge apart on a motorcycle but i suspect its just like the temp gauge you described.

How it's wired...
Voltage from the battery is applied to the fuel gauge (E-F gauge) it then goes to the sender (float unit in tank) which is a variable resistor, low resistance=high current flow, high resistance=low current flow, to complete the circuit you must have a return circuit back to the battery (wires, frame ect.) or there is no way current will flow, the more current flow (less resistance) the indicator will move in one direction less current (more resistance) the opposite direction. as you look at it a very simple circuit.
p.s. the temp SENDER (used with a temp gauge) you described was a variable resistor also.

[rustybronco]

one thing to consider, the gauge is made to work with a MINUMUM (let's say 20 ohms) resistance, if you short it to direct to ground (eliminating the sender) to check the gauge operation the current flow will be too high and possibly burn out the gauge, it must have a certain resistance as a minimum to prevent damage to the gauge. is the gauge still good?

****obvious question, how much gas is in the tank?****
you said it was between the red and white if i remember correctly.

simple?? check for continuity and shorts...

all connections must be clean first!

record the voltage across the battery terminals.
disconnect the sender wires at the tank
turn the ignition switch on
switch the voltmeter to 20v d.c. scale.
hook the negative of your voltmeter to the negative terminal of the battery.
you should have at or near battery voltage on the wire TO the gauge and about the same coming out of the gauge TO the sender with the sender still disconnected.
check the voltage of the wire AT the sender coming from the gauge, at that wire you should have about the same voltage as at the gauge with the sender still disconnected.
turn ignition key off
switch voltmeter to ohms.
measure the resistance from the OTHER wire at the sender (ground side) it should read about (i'm guessing here) 2? ohms.
disconnect the wire at the gauge coming FROM the gauge to the sender (leaving it disconnected at the sender) touch the red (positive) lead of the voltmeter to the wire just described it should read infinite (no resistance, OL ect.)

i don't have a wiring diagram i'll see if i can scrounge one up if needed.

[J_C]

The bike is equipped with an alternate fuel level indicator: the petcock.

No reserve in his bike tank, I suspect