Fuel Tank Unit: Description and Operation

Fuel Filler Cap:

Subassemblies Of Modular Fuel Sender:

Fuel Level Sensor:

MODULAR FUEL SENDER ASSEMBLY
The modular fuel sender assembly mounts in the top of the fuel tank and is spring loaded to the bottom. It is designed to:

^ Provide optimum fuel level in the internal fuel reservoir during all fuel tank levels and driving conditions.
^ Improve the measuring accuracy of fuel tank level.
^ Coarse filters contaminates from the fuel.
^ House fuel pump and helps prevent fuel pump noise.
^ Include a check valve to inhibit back flow of fuel from fuel system.

The fuel sender consists of the following serviceable components: fuel strainer, and level sensor.

FUEL PUMP
An electric fuel pump located in the modular sender assembly is used to provide fuel pressure. To control fuel pump operation, a fuel pump relay and fuel pump switch are used.

When the ignition lock cylinder is turned to "RUN" position, the fuel pump relay activates the electric fuel pump for approximately two seconds to prime the injectors. If the Powertrain Control Module (PCM) does not receive reference pulses from the distributor/crankshaft sensor after this time, the PCM opens the fuel pump relay ground circuit. The relay will reactivate the fuel pump when the PCM receives distributor/crankshaft sensor reference pulses or when oil pressure raises.

FUEL PUMP STRAINER
A woven plastic strainer is located on the lower end of the fuel sender. This filter prevents dirt from entering the fuel line and also stops water unless the filter becomes completely submerged in water. This filter is self cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment or water. Therefore, should this occur, the fuel tank should be removed and thoroughly cleaned and the tank filter replaced.

FUEL LEVEL SENSOR
The fuel sensor is attached to the modular fuel sender. The resistance of the fuel sensor changes with fuel by means of a rheostat. It ranges from 90 ohms with a full tank to 0 ohms with an empty tank.