Fuelgauge Troubles

Started by g40will, November 11, 2012, 02:55:28 PM

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g40will

im having problems with my fuel gauge and just woundering if any one can help, i cant for the life of me work it out ive try 3 diffrent lift pumps (all 3 known working) 2 diffrent sets of clocks (also all work fine on other polos) and i have line tested the wires. any help would be greatly appreciated its got me well and truly stumped ; )

cheys03

Does the gauge stick on full or empty?
If always full, you have a short. If always empty, you have a break in the wiring.
You mention you've changed the lift pump, but did this include the level float and it's carbon track too? Does the needle move at all as you plug/unplug the level sensor at the tank?
Have you tried leaving the lift pump/level sensor in the tank (to reduce the risk of fire), unplugging the pump/level sensor and connecting the cable to one of your spares, then manually moving the level float to see if anything changes?
Have you tested your replacement level sensors with a multimeter to be sure the resistance changes as you move the float?

g40will

Yeh its stuck on empty, all the lift pumps i tried had the floats intact one of them came out of my other polo, the needle does not move when you unplug it, i have tried anouther pump manualy that also did nothing, im goin to borrow a multi meter tonite and test it cheers will

cheys03

I think I got the full/empty open circuit/short the wrong way round.

Always empty = short
Always full = open circuit

You can test it by shorting the pin for the float sensor at the fuel tank end of the wire to ground.

g40will

any idea which pin is the sensor pin someone told me about this but i just  kept on blowing fuses so gave up? cheer again ; )

cheys03

Live to the fuel pump is red&yellow. Don't short this with anything.
Of the other two pins, ground is probably brown (confirm with meter) and the signal wire for the fuel gauge probably two other colours. Short these two and see if anything changes. Good luck!

cheys03

p.s fingers crossed nothing in the clocks have blown if you put 12v from the fuel pump to the level sensor wire.

g40will

Yeh checked that ive got a short on my signal wire, im just goin to run a new signal wire as the short is nowere to be seen. cheers for your help it had me baffled ; )