Fuel gauge

[malsgoing130]

Hi all,
Tearing my hair out trying to solve this problem on my own so now its time to ask the experts. The fuel gauge on my defender tdi is acting really strangely, its in a long rang tank and if i put 50 litres in it works fine, put 100 litres in the other day and gauge went all the way to bellow empty and now as I have used some diesel it has started reading again, why is it doing this? any advice?
Thanks as usual
Malcolm

[JDNSW]

This indicates that the sender is going open circuit at high fuel levels. The sender has a contact that moves along a coil of resistance wire as the level changes. The symptoms indicate that the coil of resistance wire has a break in it, or the contact is not touching it at the "full" end. I cannot remember how easy it is to get at the works of these - it could possibly be just a matter of bending a mounting bracket so the contact bears evenly on the coil. The alternative would be to replace it or get it repaired if this is feasible - there may be someone who does this, although I don't know of any.

John

[Scouse]

I have a Tdi sender unit in another car & it has a couple of dead spots in the variable resistor in the sender unit. It does the same as yours depending on fuel level.

[malsgoing130]

do you think its worth replacing? after market unit is about $80? sounds like a fun job removing it according to previous threads.
thanks for the replies above.
Malcolm