strange things with the fuel guage???

[Mechman]

hi guys.
have wired up and sorted the fuel guage on the 40... but i seem to have a very strange problem with it. one moment its showing the fuel level in the tank.. 30 secs later is showing empty... then 30 secs later its back to the level again..


BIZAREO!

any ideas?

cheers

Rob

[DAZZ]

Do these have a voltage stabiliser in the gauge cluster???

Might be U\S if it does!!!!

[Mechman]

umm, this was built in 1973... does that answer your question?
i have no idea...

it is very bizar to watch...lol

[DAZZ]

Will see if there is a wiring diag at work. Fairly certain that the do as most jap stuff does....

[Mechman]

that would be awsome Dazz, thanks.

[-Scott-]

Rob

The sender is typically a variable resistor. The float is on the end of an arm which moves the wiper contact. If the wiper contact is a bit dodgy (worn/dirty) contact can become intermittent, and an open circuit is high resistance = empty?

On my old Galant the wiper contact was a dimple in a piece of sheet metal. Over 20+ years the dimple wore away to almost nothing, and started to behave as you describe.

If a good clean doesn't fix the problem I'm not sure what the next solution would be - chances are any replacements from a wrecker would be as worn, although you might get lucky and find a later model sender can be made to fit.

Good luck,

Scott

[Mechman]

thanks for that Scott,
i think you could be right here. i will take the sender unit out and see if i can simulate the problem.

fingers crossed its just my goober wiring...lol


Rob

[mud4b]

just something to try....

sierras (and most probebly your rig) have and earth wire going from the chassis to the body.....

if this snaps or the earth is crap your fuel guage tends to go bonkers...

have a look around and see what you can find...

[Mechman]

thanks mud4b.
drove me mad this weekend away.... grrrrrr