The fuel tank is used to store fuel for the vehicle. The tank is located in the rear of the vehicle and is held in place by two metal straps that are attached to the underbody. The fuel tank is made of steel and is coated internally with a special corrosion inhibitor. Due to the internal coating of the fuel tank, the fuel tank is not repairable.The fuel tank shape includes a reservoir in order to maintain a constant supply of fuel around the fuel pump strainer during low fuel conditions and aggressive vehicle maneuvers. A fuel tank filler pipe check-valve tube is attached to the fuel tank and extends from the fuel tank inlet to the reservoir. The fuel tank filler pipe check-valve is located inside the fuel tank filler pipe check-valve tube and prevents fuel from splashing back out of the fuel tank filler pipe during refueling.

In order to prevent refueling with leaded fuel, the fuel tank filler pipe (2) has a built-in restrictor and deflector. The fuel tank filler pipe is connected to the fuel tank filler extension (1) by clamps.

The fuel tank filler pipe is equipped with a threaded-type fuel tank filler pipe cap. The threaded part of the fuel tank filler pipe cap requires several turns counterclockwise before it can be removed. A built-in torque-limiting device prevents over tightening of the fuel tank filler pipe cap. In order to install the fuel tank filler pipe cap, turn the fuel tank filler pipe cap clockwise until at least 3 clicking noises are heard. The clicking noises signal that the correct torque has been reached and that the fuel tank filler pipe cap is fully seated. The Enhanced EVAP fuel tank pipe cap has a tether connected to the fuel filler door.

Notice: Use a fuel tank filler pipe cap with the same features as the original when a replacement is necessary. Failure to use the correct fuel tank filler pipe cap can result in a serious malfunction of the fuel system.

The fuel tank pressure sensor is a three wire strain gauge sensor much like that of the common GM MAP sensor. However, this sensor has very different electrical characteristics due to its pressure differential design. The sensor measures the difference between the air pressure (or vacuum) in the fuel tank and the outside air pressure. The sensor mounts at the top of the fuel tank. A three wire electrical harness connects it to the Powertrain Control Module (PCM). The PCM supplies a five volt reference voltage and ground to the sensor. The sensor will return a voltage between 0.1 and 4.9 volts. When the air pressure in the fuel tank is equal to the outside air pressure, such as when the fuel fill cap is removed, the output voltage of the sensor will be 1.3 to 1.7 volts.

The modular 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 modular fuel sender assembly consists of the following major components: a fuel pump, a fuel sender strainer (3), a fuel pump strainer, a roll-over valve (2), a fuel level sensor (4), and, a fuel tank pressure sensor (6).

The fuel sender consists of the float, the wire float arm, and the rheostat. The rheostat is mounted on the fuel sender and located in series with the voltage supply circuit from the fuel gage or body control module (BCM). As the position of the float varies with the fuel level, the rheostat produces a variable resistance between the fuel gage or BCM and ground. The fuel gage converts this variable resistance into the fuel level reading display 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 EVAP canister if the vehicle rolls over by shutting OFF the EVAP pipe to the evaporative emission canister.

A high pressure gerotor fuel pump is mounted to the fuel sender 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. Refer to Fuel Pump Electrical Circuit Diagnosis .

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. Refer to Fuel System Cleaning .

A fuel filter is used in the fuel feed pipe ahead of the fuel injection system. The fuel filter is mounted directly in front of the fuel tank. The fuel filter housing (1) is constructed of steel with a quick-connect fitting at the inlet of the fuel filter and a threaded fitting at the outlet of the fuel filter. The threaded fitting is sealed with an O-ring, which is replaceable. The filter element (2) is made of paper and is designed to trap particles suspended in the fuel that may damage the injection system.

There is no service interval for in-pipe fuel filter replacement. Only replace the in-pipe fuel filter if it is restricted.

The fuel feed and fuel return pipes carry fuel from the fuel sender assembly to the fuel injection system and back to the fuel sender assembly.

Caution: In order to Reduce the Risk of Fire and Personal Injury:

Nylon fuel pipes are designed to perform the same job as the steel or rubber fuel lines they replace. Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives and changes in temperature. There are two sizes used: 3/8" ID for the fuel feed, and 5/16" ID for the fuel return and are used on the modular sender. Nylon fuel pipes are somewhat flexible and can be formed around gradual turns. However, if forced into sharp bends, nylon pipes will kink and restrict fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Special care should be taken when working on a vehicle with nylon pipes.

Quick-connect type fittings provide a simplified means of installing and connecting fuel system components. Depending on the vehicle model, there are two types of quick-connect fittings, each used at different locations in the fuel system. Each type of quick-connect fitting consists of a unique female connector and a compatible male fuel pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs or fingers hold the quick-connect fittings together.

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.

The enhanced EVAP service port is located in the evaporative purge hose between the purge solenoid and the canister. The service port is identified by a green colored cap. The port contains a schrader valve and fittings to allow connections of