Notice: Do not use fuels containing methanol in order to prevent damage and corrosion to the fuel system.
The fuel supply is stored in the fuel tank. An electric fuel pump, which is located in the fuel tank with the fuel level sensor sending unit, pumps fuel through an in-line fuel filter to the engine. The pump provides fuel at a pressure greater than is needed by the injectors. The fuel pressure regulator keeps fuel available to the injectors at a regulated pressure. The unused fuel is returned to the fuel tank by a separate line.
Fuel Tank
The fuel tank, at the rear of the underbody, is held in place by 2 metal straps. Anti-squeak pieces are used on top of the tank to reduce rattles.
Filler Neck
In order to help prevent refueling with leaded gasoline, the fuel filler neck on vehicles with gasoline engines has a built-in restrictor and deflector. The opening in the restrictor will only admit the smaller unleaded gas nozzle spout, which must be fully inserted to bypass the deflector.
Attempting to refuel with leaded gas, or failure to fully insert the unleaded gas nozzle into the fuel filler neck results in gasoline splashing back out of the filler neck.
Fuel Filler Cap
Notice: If a fuel tank filler pipe cap requires replacement, use only a fuel tank filler pipe cap with the same features. Failure to use the correct fuel tank filler pipe cap can result in a serious malfunction of the fuel system.
The fuel tank filler neck is equipped with a quarter-turn type fuel filler cap. A built in ratchet type torque limiting device prevents over tightening of the cap. In order to install the fuel filler cap, turn the cap clockwise until a clicking noise is heard. This signals that the correct torque has been reached and the fuel filler cap is fully seated. A fuel filler cap that is not fully seated, may cause a malfunction in the emission system.
Modular Fuel Sender Assembly
The modular fuel sender assembly mounts in the top of the fuel tank and is spring loaded to the bottom. The modular fuel sender assembly is designed to do the following:
| • | 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 |
| • | Filter coarse contaminates from the fuel |
| • | House the fuel pump and help prevent fuel pump noise |
| • | Inhibit back flow of fuel from fuel system through the use of a check valve |
The fuel sender consists of the following serviceable components:
| • | A fuel strainer (3) |
| • | A fuel level sensor (4) |
| • | A fuel tank pressure sensor (1) |
Fuel Pump
An electric fuel pump located in the modular sender assembly (2) is used to provide fuel pressure. To control fuel pump operation, a fuel pump relay and fuel pump switch are used. When the ignition switch is turned to the RUN position, the fuel pump relay activates the electric fuel pump for approximately two seconds to prime the fuel injectors. If the PCM does not receive reference pulses after this time, the PCM opens the fuel pump relay voltage circuit. The relay will reactivate the fuel pump when the PCM receives reference pulses.
Fuel Tank Pressure Sensor
The fuel tank pressure sensor (1) is mounted on top of the modular fuel sender. The sensor measures the difference between the fuel vapor pressure (or vacuum) in the fuel tank and the outside air pressure. A three wire electrical harness connects it to the powertrain control module (PCM). The PCM supplies a 5 volt reference signal and a ground to the sensor. The sensor returns a voltage between 0.1 volts-4.9 volts back to the PCM, depending on the fuel vapor pressure in the fuel tank. When the fuel pressure in the tank is equal to the outside air pressure, such as when the fuel cap is removed, the sensor output voltage will be between 1.3-1.7 volts.
Fuel Pump Strainer
A woven plastic strainer (3) is located on the lower end of the fuel sender. This filter prevents dirt from entering the fuel pipe and also stops water unless the filter becomes completely submerged in water. This 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. Should this occur, the fuel tank should be removed and thoroughly cleaned and the fuel pump strainer replaced.
Fuel Level Sensor
The fuel sensor (4) is attached to the modular fuel sender. The resistance of the fuel level sensor changes with the fuel by means of a rheostat. As the position of the float varies with the fuel level, the rheostat produces a variable resistance. The fuel gauge converts this variable resistance into the fuel level reading displayed on the instrument panel.
Fuel And Vapor Pipes
The fuel feed and return pipes and hoses extend from the fuel pump and the sender to the injection unit. The fuel feed and return pipes and hoses are routed along the frame side member.
The vapor pipe and hoses extend from the fuel pump and the sender unit to the evaporative emission (EVAP) control vapor canister.
In-Line Fuel Filter
A stainless steel in-line fuel filter is used in the fuel feed line ahead of the fuel injection system. The steel filter housing (1) is constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. The filter element (2) is made of paper, and is designed to trap particles in the fuel that may damage the injection system.
