Fuel Delivery System
FUEL DELIVERY SYSTEMThe vehicle uses a plastic fuel tank located rear center of the vehicle.
The Fuel Delivery System consists of: the electric fuel pump module, fuel filter, tubes/lines/hoses, fuel rail, and fuel injectors.
The in-tank fuel pump module contains the fuel pump. The pump is serviced as part of the fuel pump module. Refer to Fuel Pump Module.
The fuel filter is a replaceable in-line filter. The filter attaches to a bracket mounted on the fuel tank. Refer to the Maintenance Schedules in the Introduction for recommended fuel filter replacement intervals.
FUEL PUMP MODULE - ALL
Fuel Pump Module - Typical:
The fuel pump module contains the fuel pump, fuel reservoir, level sensor, and inlet strainer. The inlet strainer, level sensor and rollover valve are the only serviceable items. If the fuel pump requires service, replace the fuel pump module.
ELECTRIC FUEL PUMP
The fuel system uses a positive displacement, gerotor gear, immersible pump with a permanent magnet electric motor. The pump draws fuel through a strainer and pushes it through the motor to the outlet. The fuel pump module is suspended in fuel in the tank. The pump module contains two check valves. One valve relieves internal fuel pump pressure and regulates maximum pump output. The second valve, in the pump outlet, maintains pump pressure during engine off conditions. The fuel pump relay provides voltage to the fuel pump.
The fuel pump has a maximum unregulated pressure out~ut of approximately 871 kPa (125 psi). Without vacuum applied to the fuel pressure regulator, the regulator adjusts fuel system pressure to approximately 338 kPa (49 psi) on 3.5L engines. Fuel system pressure varies with different amounts of manifold vacuum.
FUEL LEVEL SENSOR
The level sensor is mounted to the side of the fuel pump module in the fuel tank. The level sensor is a variable resistor. Its resistance changes with the amount of fuel in the tank. The float arm attached to the sensor moves as the fuel level changes.
FUEL TANK
The fuel tanks of all Chrysler Motors built vehicles are equipped with fuel and vapor controls that allow the vehicle to pass a full 360° rollover without fuel leakage.
The fuel delivery systems contain a fuel tank rollover valve. The valve is mounted on top of the fuel tank. The valve functions as a check valve that prevents fuel from escaping from the fuel tank when the vehicle is turned over.
The fuel filler cap acts as a pressure/vacuum relief valve. When air pressure inside the fuel tank gets too high or too low, the fuel filler cap opens to relieve the difference in pressure.
An evaporation control system restricts fuel evaporation into the atmosphere and reduces unburned hydrocarbons. Vapors from the fuel tank are collected in a charcoal filled canister. The vapors are held in the canister until the engine is operating. When the engine is running, the vapors are drawn through the intake manifold into the combustion chambers.
1999 FUEL INJECTORS
Fuel Injector:
The fuel injectors are 12 ohm electrical solenoids. The injector contains a pintle that closes off an orifice at the nozzle end. When electric current is supplied to the injector, the armature and needle move a short distance against a spring, allowing fuel to flow out the orifice. Because the fuel is under high pressure, a fine spray is developed in the shape of 2 streams. The spraying action atomizes the fuel, adding it to the air entering the combustion chamber. The injectors are positioned in the cylinder heads. Fuel injectors are not interchangeable between engines.
Fuel Injector Location - Typical:
The injectors are positioned in the cylinder heads with the nozzle ends directly above the intake valve port.
1999 FUEL PRESSURE REGULATOR
The fuel system uses a nonadjustable pressure regulator that maintains fuel system pressure at approximately 338 kPa (49 psi), 3.31 uses approximately 379 kPa (55 psi). The fuel pressure regulator contains a diaphragm, calibrated spring and a fuel return valve. The spring pushes down on the diaphragm and closes off the fuel return port. System fuel pressure reflects the amount of fuel pressure required to open the return port.
The pressure regulator is a mechanical device that is NOT controlled by the PCM or engine vacuum.
PRESSURE - VACUUM FILLER CAP
The fuel filler cap incorporates a two - way relief valve that is closed to atmosphere during normal operating conditions. The relief valve is calibrated to open when a pressure of 10 kPa (1.5 psi) or vacuum of 6 kPa (1.8 in. Hg) occurs in the fuel tank. When the pressure or vacuum is relieved, the valve returns to the normally closed position.
CAUTION: Remove the fuel filler cap to release fuel tank pressure before disconnecting any fuel system component.
QUICK - CONNECT FITTINGS
Different types of quick - connect fittings are used to attach various fuel system components. These are: a single - tab type, a two - tab type or a plastic retainer ring type. Some are equipped with safety latch clips. Refer to the Removal/Installation for more information.
CAUTION: The interior components (O-rings, spacers) of quick - connect fitting are not serviced separately. Do not attempt to repair damaged fittings or fuel lines/tubes. If repair is necessary, replace the complete fuel tube assembly.
Plastic Quick-Connect Fittings:
Fuel tubes connect fuel system components with plastic quick-connect fuel fittings. The fitting contains non - serviceable O-ring seals.
CAUTION: Quick - connect fittings are not serviced separately. Do not attempt to repair damaged quick - connect fittings or fuel tubes. Replace the complete fuel tube/quick-connect fittings assembly.
The quick-connect fitting consists of the 0-rings, retainer and casing. When the fuel tube enters the fitting, the retainer locks the shoulder of the nipple in place and the O-rings seal the tube.
ROLLOVER VALVE
The fuel tank has fuel and vapor controls that allow the vehicle to pass a full 360 ° rollover without fuel leakage.
The valve also contains a check valve that prevents fuel from escaping the fuel tank if the vehicle rolls over.