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 more 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 storage tank is made of steel and is coated internally with a special corrosion inhibitor and is located in front of the rear wheels. It is held in place by two metal straps attached to the under body of the vehicle.
Fuel Tank Filler Neck
To help prevent refueling with leaded fuel, the fuel filler neck (1) has a built in restrictor and deflector. The opening in the restrictor will accept only the smaller unleaded gasoline fuel nozzle which must be fully inserted to bypass the deflector.
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 (1) is equipped with a screw type cap (2). The threaded part of the cap requires several turns counter-clockwise in order for removal. A built in ratchet type torque limiting device prevents over tightening. In order to install, turn the cap clockwise until a clicking noise is heard. This signals that the correct torque has been reached and the cap is fully seated. A fuel filler cap that is not fully seated, may cause a malfunction in the emission system.
Fuel Sender Assembly
The fuel sender assembly is attached to the top of the fuel tank, and extends from the top of the fuel tank to the reservoir.
The fuel sender assembly consists of the following major components: a fuel sender (1), a fuel pump (2), a fuel pump strainer (3), and a roll-over valve .
The fuel sender consists of the float (4), the rheostat and the roll-over valve. The fuel level is sensed by the position of the float and float arm, which operate the 90 ohms rheostat. As the float position changes, the amount of current passing through the rheostat varies, thus changing the Gauge reading on the instrument panel.
The roll-over valve is pressed into the EVAP pipe of the fuel sender and is not serviced separately. The roll-over valve prevents fuel from entering the engine compartment if the vehicle rolls over by shutting OFF the EVAP pipe to the evaporative emission canister.
Fuel Pump
A high pressure roller vane fuel pump (2) is mounted to the fuel sender (1) inside the fuel tank. The fuel is pumped to the engine at a specified flow and pressure through the fuel pump. Excess fuel is returned to the fuel tank by a 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 strainer is located on the lower end of the fuel sender. This strainer prevents dirt from entering the fuel sender and also stops water unless the strainer becomes completely submerged in water. This 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. Therefore, should this occur, the fuel tank should be removed and thoroughly cleaned and the strainer replaced.
Fuel Level Sensor
The fuel sensor is attached to the modular fuel sender. The resistance of the fuel sensor changes with the fuel level 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.
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. A quick-connect type fitting is used at one end and an O-ring where the fuel pipe screws into the fuel filter body on the other end.
Fuel Feed and Return Pipes And Hoses
The fuel feed (1) and return hoses (2) and lines carry fuel from the fuel tank to the lower manifold assembly and back to the fuel tank.
Nylon Fuel Pipes
Caution: In order to Reduce the Risk of Fire and Personal Injury:
• If nylon fuel pipes are nicked, scratched or damaged during installation,
Do Not attempt to repair the sections of the nylon fuel pipes. Replace them. • When installing new fuel pipes, Do Not hammer directly on the
fuel harness body clips as it may damage the nylon pipes resulting in a possible
fuel leak. • Always cover nylon vapor pipes with a wet towel before using a
torch near them. Also, never expose the vehicle to temperatures higher than
115°C (239°F) for more than one hour, or more than 90°C (194°F)
for any extended period. • Before connecting fuel pipe fittings, always apply a few drops
of clean engine oil to the male pipe ends. This will ensure proper reconnection
and prevent a possible fuel leak. (During normal operation, the O-rings located
in the female connector will swell and may prevent proper reconnection if
not lubricated.)
Nylon fuel pipes are designed to perform the same job as the steel or rubber fuel lines that they replace. The nylon pipes are constructed to withstand the maximum fuel system pressure, exposure to fuel additives and changes in temperature. There are two sizes used: 3/8 inch ID for the fuel feed, and 5/16 inch ID for the fuel return and are used on the modular sender. The nylon fuel pipes are somewhat flexible and can be formed around gradual turns. However, if forced into sharp bends, the nylon pipes will kink and restrict the fuel flow. Also, once exposed to fuel, the nylon pipes may become stiffer and are more likely to kink if bent too far. Take special care when working on a vehicle with nylon pipes.
Quick-Connect Fittings
Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end on the fuel rail. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs or fingers hold the fittings together.
Fuel Pipe O-Rings
Fuel feed and return pipe threaded connections at the fuel rail and fuel filter are sealed with replaceable O-ring seals. These O-rings seals are made of special material, and should only be serviced with the correct service part.
Fuel Vapor Pipe and Hoses
The fuel vapor line is made up of nylon line, steel pipe, and quick connectors. The vapor pipe, line, and hoses carry fuel vapors from the fuel tank to the charcoal canister. The vapor lines extend from the fuel sender to the canister. However, it does not follow the same route as the fuel feed pipe. Under no conditions use copper or aluminum tubing to replace steel tubing. Those materials do not have satisfactory durability to withstand normal vehicle vibrations and corrosion.
