Fuel Gauge fault - at max position

[Deuce]

Hi all,
I left work in the car the other day and noticed the fuel gauge was maxed out (should have around 3/4 tank in there).
Does anyone know if the gauge max's out when the plug is unplugged? Or does it max out when two wires short and touch each other?
I might look at this on this coming weekend if anyone can offer a heads up.

 

[krusing]

Sounds like faulty wiring, probably open circuit I would think for the gauge to max out,
Or the tank unit is faulty,
check at the tank end with a multimeter for any resistance in the fuel gauge wires.

 

[Deuce]

Yeah, thats what i was thinking.
In hindsight, I did go over a grass area when leaving work, and did hear a noise which layer looks to be the exhaust flange scraped up a little dirt. Maybe it disturbed something higher up???
Sounds like I need to get the back in the air and have a good look.
Anyone know what the FLS resistance is at full tank vs empty tank? I should be able to verify externally if my sender is good.

 

[07GTS]

if its maxed out then u have a short (dead short may cause smoke) as the ohms are empty 284 and full 40 (factory 35 sometimes) if the temp is also reading high it may be the regulated voltage to both, otherwise there is a wiring/sender issue causing it, just be careful as it may still be ok but if it goes too far u will be up for a gauge also

 

[Deuce]

if its maxed out then u have a short (dead short may cause smoke) as the ohms are empty 284 and full 40 (factory 35 sometimes) if the temp is also reading high it may be the regulated voltage to both, otherwise there is a wiring/sender issue causing it, just be careful as it may still be ok but if it goes too far u will be up for a gauge also

Awesome info. Thanks mate.

 

[Deuce]

Removed plug and probed the sender.
37ohm.
Probed wires and no continuity.
So no short in wires. And ohms are too low in tank.
So maybe when the tank is next low I'll drop it and pull the sender to check.

 

[07GTS]

usually any faults with the sender will cause it to read lower or drop out, or something has moved in the tank holding the float up to keep the lower ohms reading, 37 ohms would prob be just over full so if u find it staying up there after alot of driving and u should have less in tank shut engine off and then put ignition back on and see if its staying up full if it is then disconnect the sender plug see if it stays up or drops back if it drops back then something in the tanks is causing it so check the ohms again, also with key on check power to the sender with multimeter it should be 10v if its higher then its dash issue

 

[Deuce]

Bugger. I should have checked reading while unplugged. Oh well.
I only do 100km in it most months, but may do more. I'll keep a note on kms to gauge distance travelled.

 

[Deuce]

UPDATE.
pulled the fuel tank out (absolute sea-unt of a job), checked sender and it was still 37 ohm. Un-did pump/sender/lines front face and pulled out a little (maybe 10mm), check ohms again and it was 135. Tilted tank up and got 140, lowered down and got 128/130.
Now to just put the bugger back in.

Oh, and with rhe tank out (and all unplugged obviously) the fuel gauge stays on empty.

 

[07GTS]

just make sure the loom to pump and the return hose arnt catching on the sender arm