Fuel Guage

[dgod3]

My Volvo Penta fuel guage reads full as soon as ignition is turned on. Even when I disconnect both electrical cables at the top of the sender on the diesel tank the guage still reads full. I assume therefore that the sender must be ok, so is it the guage or a problem with the electrics/? Any clues?

 

[claudio]

Sounds like a faulty sender unit or bad return wiring (to 0V) on the sender to me.

 

[VicS]

A wiring fault I would suggest! A short between the wires or a fault to negative (earth) of one of the wires

But difficult to be sure without a circuit diagram to refer to.

 

[Refueler]

[ QUOTE ]
My Volvo Penta fuel guage reads full as soon as ignition is turned on. Even when I disconnect both electrical cables at the top of the sender on the diesel tank the guage still reads full. I assume therefore that the sender must be ok, so is it the guage or a problem with the electrics/? Any clues?

[/ QUOTE ]

It was not unknown with older car gauges to read full when faulty ... my old Land Rovers did if you disconnected leads etc. The sender unit is usually a variable rheostat and as long as gauge and sender are set for which ever way it works reducing or increasing resistance as float arm rotates rheostat ... should be ok - but they do fail .....

I'm wondering if a meter could be put across the sender output to see if it changes with arm movement ?