First trip - fuel guage problem

[Griffin]

Hi All - had my first weekend trip in my new Bongo, a few teething troubles but mainly had a great time. Anyway, one of the problems was the fuel guage, basically it works fine until I've done approx 110 miles but then drops to the empty position very rapidly. Had a panic on the motorway because although I hoped the Bongo hadn't really used a full tank of fuel I wasn't sure - turns out it was still half full.

After refilling it seemed fine, and worked Ok over a variety of shorter distances. Coming home, 110+ miles without stopping, same thing again, needle went straight to empty.

I've searched through the archives and seen mention of the earth wires being damaged/corroded however I'm not sure this would give these symptoms (happy to be corrected here).....

Can anyone help ?

[pippin]

Doubt it is the wires or earthing, but it would be a simple thing to check first.

Doubt it is the actual readout on the dash that is faulty.

More likely to be a physical problem with the gauage/guage/gauge sender itself.

[grumpo]

I have never stripped a Bongo fuel level sensor but the vast majority
of shallow tank sensors are a simple open potentiometer wich have
been reliably used for over 80 years.

The sensor is a wire wound linear resistor with a bronze or steel wiper.
If the Bongo one is the same, and I would be very suprised if it wasn't,
then your symptoms would indicate that the resistor has become open
circuit about half way along it's length. This would produce exactly the
results you described.

If this is the case, then the only option is to remove the complete unit
from the tank and physically inspect or electrically test the resistor.

[Griffin]

Thanks for the info guys, I can feel some investigation coming on. I'm guessing that a new sensor will sort it out but I imagine they aren't cheap.

No doubt I'll be back for more advice soon You never know with all the stuff I am learning I may be able to offer some as well.