I have a 1997 Disco I with an inaccurate gas guage. What is the most common problem and repair? Vehicle runs great, fuel pump is fine but before i try getting into the sending unit i thought i'd ask some professionals. Bad wire on sending unit? How costly and difficult to repair?

Thanks

 

IMHO if it works at all, other than a check of the connector, I'd leave it alone. More brittle plastic parts inside the pump assembly. Just fill up every 150 miles.
The RAVE shop manual says it will read 19 ohms at full, and 245 at bone dry.

 

Mine is inaccurate too since replacement depending on the amount of ethanol in the fuel I bought.
Ethanol has a different specific gravity than gasoline and the float will float at a different level.

 

The contact points (Potentiometer) on the fuel pump is wearing down....

I had that issue where it failed completely, and to fix it was simply to replace the pump assembly.

 

Yea it's either the contact points for the gauge in tank on pump, but also the sending wire can fray and break making inaccurate or empty readings this can be re soldered with a solder that can hold up to fuel submersion. This wire is bare and not sheathed making it prone to breakdown from years of fuel submersion. Pump R&R is quite easy but yes lots of brittle parts so care should be taken.