Fuel Gauge Issues.

[Dougal]

For some time now (like as long as I've owned this truck), my fuel gauge and temperature gauge have followed each other.

Last weekend I attemped to fix that, by isolating the +10v end of the fuel gauge and installing a seperate voltage regulator.

But the ghost of lucas won't let me.

Even when the bloody thing was isolated (i.e. nothing for the power to jump through), I have 10v at the "isolated" post.

Teeing off the power supply lead for the existing voltage regulator has given me more problems. For some reason the regulators fight each other, each drawing soo much current they heat up and burn out the copper tracks feeding it.

I get 100 ohms resistance (60 in the gauge, 40 more from the tank lead) which should give only 0.1 amps. Not enough to heat each reg to burn the fingers or burn out copper tracks.

Has anyone else found a solution to this problem?
Hell has anyone else even had this problem?

[Diesel Jim]

Is this on defender/90/110? the guages on those have to have 3 connetions... the "+ve" fed, the one that goes to the tank/temp sender, and the actualy metal can of the guage itself has an earth to it too.

if the earth off of the can is lost, then the guage usually goes right up off the scale. maybe you've lost that???

[Dougal]

Originally Posted by Diesel Jim

Is this on defender/90/110? the guages on those have to have 3 connetions... the "+ve" fed, the one that goes to the tank/temp sender, and the actualy metal can of the guage itself has an earth to it too.

if the earth off of the can is lost, then the guage usually goes right up off the scale. maybe you've lost that???

This is on a RRC, but yes they suffer the same earth problem.

I've got two "extra" earth leads in my instruments, on the voltage regulator earth (helped heaps) and the extra rev counter earth (stopped the needle dropping when the lights were switched on).

Don't we love lucas

Do you know if the fuel light works of the same circuit as the gauge or is it a seperate switch?