Roadmaster V8-350 5.7L VIN P MFI (1995)
Fuel Sender
FUEL TANK UNIT
The fuel tank unit is located inside the fuel tank and is attached to the top of the fuel tank.
The fuel Tank Unit consists of the following major components: a fuel sender, fuel pump, and a fuel pump strainer.
Fuel Sender Assembly
The fuel sender consists of the float, wire float arm, rheostat and roll-over valve. Fuel level is sensed by the position of the float and float arm
which operate the 90 ohm rheostat. As the float position changes, the amount of current passing through the rheostat varies, thus changing the gage
reading on the instrument panel.
The roll-over valve is pressed into the evaporative emission (EVAP) pipe of the fuel sender and is not serviced separately. The roll-over valve
prevents fuel from entering the evaporative emission canister if the vehicle rolls over by shutting "OFF" the EVAP pipe to the canister.
Fuel Pump
The fuel pump is an electric medium pressure twin turbine pump which is mounted to the fuel sender assembly inside the fuel tank. The fuel is
pumped to the fuel rail assembly at a specified flow and pressure by the fuel pump. Excess fuel is returned to the fuel tank by the return pipe. The
fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers.
The electric fuel pump operation is controlled by the Powertrain Control Module (PCM) through a fuel pump relay.
Fuel Pump Strainer
A woven plastic fuel pump strainer is attached to the lower end of the fuel pump in the fuel tank. The functions of the fuel pump strainer are to
filter contaminants and to wick fuel.
The life of the fuel pump strainer is generally considered to be that of the fuel pump. The fuel pump strainer 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. In which case the tank
should be thoroughly cleaned. (See "Fuel System Cleaning.") If the fuel pump strainer is plugged, replace it with a new fuel pump strainer.
