Discovery II
FUEL DELIVERY SYSTEM - V8
19-2-8
DESCRIPTION AND OPERATION
Fuel gauge sender
The fuel gauge sender unit comprises a rotary potentiometer operated by a float. The float rises and falls with the fuel
level in the tank and moves the potentiometer accordingly.
Battery voltage is supplied to the potentiometer. The output voltage from the potentiometer varies according to the
resistance through the potentiometer in relation to the fuel level. The output voltage is connected to the fuel gauge in
the instrument pack. The fuel gauge receives a battery voltage input and this is compared with the output voltage from
the potentiometer. The difference between the two voltages determines the deflection of the fuel gauge pointer.
Fuel gauge reading
Tank volume litres (US Gallons) *
Sender unit resistance
ohms
Ω
FULL
95 (25)
15
3/4
71 (18.8)
36
1/2
48 (12.7)
64
1/4
24 (6.4)
110
RESERVE (fuel light ON)
11 (2.9)
158
EMPTY
0 (0)
245
*Tank volumes are approximate.
