Water In Fuel Indicator: Testing and Inspection

Fig. 4 Water in fuel detector & tank purge procedure. 1980---84:

DESCRIPTION & OPERATION
1980---84
The Water In Fuel warning system employs an electronic water detector mounted inside the fuel tank on the fuel gauge sending unit. The detector provides a warning when 1---21/2 gallons of water are present in the fuel tank by lighting a warning lamp on the instrument panel. The sending unit assembly also contains a provision for siphoning off water in the fuel tank through the fuel return line, Fig. 4.
The Water In Fuel lamp will come on for 2---5 seconds each time ignition is switched to Run position to ensure lamp is operating. If water is present in fuel, the lamp will come on after a 15---20 second delay and remain on.

Fig. 5 Water in fuel detector. 1985---88:

1985---88
The Water In Fuel warning system employs a fuel detector integral with the fuel filter and fuel heater, Fig. 5, and mounted on the engine. When more than 2.2 ounces of water has collected in the filter, the Water In Fuel lamp on the instrument panel will light. After the light comes on, the filter should be drained as soon as possible and must be drained within 2 hours of operation.




TROUBLESHOOTING
1980---84
1. If warning indicator fails to light during bulb check, proceed as follows:
a. Disconnect electrical connector from fuel gauge sensing unit.
b. Ground yellow/black wire in connector, then turn ignition to Run position.
c. If indicator lamp lights, remove fuel gauge tank unit and check yellow wire for opens. Also, check connections to Water In Fuel detector and mounting screws. If connections and attachments are satisfactory, replace detector.
d. If indicator lamp fails to light, check indicator lamp bulb. If bulb is satisfactory, check for open in yellow wire between lamp socket and sending unit and repair as necessary.
2. If warning indicator is lit at all times, proceed as follows:
a. Disconnect electrical connector from fuel gauge sending unit, then turn ignition to Run position.
b. If light remains lit, repair short to ground in yellow/black wire between sender and warning lamp.
c. If light goes out, drain water from fuel tank, then recheck circuit. If lamp remains on with harness connected to sending unit, wiring to water detector or the detector itself is at fault.