Fuel Delivery System
SYSTEM OPERATIONThe front wheel drive van uses a plastic fuel tank located on the left side 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 and pressure regulator. 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 top of the fuel tank. Refer to the Maintenance Schedules in the Introduction for recommended fuel filter replacement intervals.
A returnless fuel system is used on all vehicles. Fuel is returned through the fuel pump module and back to the fuel tank. A separate fuel return line from the tank to the engine is no longer used.
Fuel Pump Module:
FUEL PUMP MODULE
DESCRIPTION
The fuel pump module is installed in the top of the fuel tank.
The fuel pump module contains the following:
- Electric fuel pump
- Fuel pump reservoir
- Inlet strainer
- Fuel pressure regulator
- Fuel gauge sending unit
- Fuel supply line connection
The inlet strainer, fuel pressure regulator and fuel level sensor are the only serviceable items. If the fuel pump or electrical wiring harness requires service, replace the fuel pump module.
The electric fuel pump is located in and is part of the fuel pump module. It is a positive displacement, gerotor type, immersible pump with a permanent magnet electric motor.
OPERATION
The pump draws fuel through a strainer and pushes it through the motor to the outlet, The pump contains one check valve. The check 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 deadheaded pressure output of approximately 635 kPa (95 psi). The regulator adjusts fuel system pressure to approximately 338 kPa (49 psi).
Fuel Pump Electrical Control
Voltage to operate the electric pump is supplied through the fuel pump relay. For an electrical operational description of the fuel pump refer to fuel Pump Relay-PCM Output.
Electrical Pump Replacement
The electric fuel pump is not serviceable. If the fuel pump or electrical wiring harness needs replacement, the complete fuel pump module must be replaced. Perform the Fuel System Pressure Release procedure before servicing the fuel pump.
FUEL LEVEL SENSOR
DESCRIPTION
The level sensor is attached to the side of the fuel pump module. The level sensor consists of a float, an arm, and a variable resistor.
OPERATION
As the fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the fuel gauge on the instrument panel to read full.
FUEL PRESSURE REGULATOR
OPERATION
The fuel system uses a nonadjustable pressure regulator that maintains fuel system pressure at approximately 338 kPa (49 psi), 3.31 FFV 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.
FUEL INJECTORS
DESCRIPTION
Fuel Injector Location - Typical:
The injectors are positioned in the intake manifold with the nozzle ends directly above the intake valve port.
OPERATION
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 a hollow cone. The spraying action atomizes the fuel, adding it to the air entering the combustion chamber. Fuel injectors are not interchangeable between engines.
FUEL TANK
SYSTEM OPERATION
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° over without fuel leakage.
Front Wheel Drive fuel delivery systems contain a fuel tank rollover valve. The valve is mounted on top of the fuel tank. The valve functions as a tank pressure control valve while the vehicle is upright, but contains 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.
ROLLOVER VALVES
DESCRIPTION
All vehicles have rollover valve(s) on top of the fuel tank.
OPERATION
The valves prevent fuel flow through the fuel tank vent valve hoses should the vehicle rollover.
The rollover valves on the fuel tank are not serviceable.
Proportion Purge Solenoid:
PROPORTIONAL PURGE SOLENOID
OPERATION
All vehicles use a proportional purge solenoid. The solenoid regulates the rate of vapor flow from the EVAP canister to the throttle body. The PCM operates the solenoid.
During the cold start warm-up period and the hot start time delay, the PCM does not energize the solenoid. When de-energized, no vapors are purged.
The proportional purge solenoid operates at a frequency of 200 hz and is controlled by an engine controller circuit that senses the current being applied to the proportional purge solenoid and then adjusts that current to achieve the desired purge flow. The proportional purge solenoid controls the purge rate of fuel vapors from the vapor canister and fuel tank to the engine intake manifold.
QUICK-CONNECT FITTINGS
DESCRIPTION
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 fitting assembly.
The quick-connect fitting consists of the O-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.
FUEL TUBES/LINES/HOSES AND CLAMPS
OPERATION
Also refer to Quick-Connect Fittings.
WARNING: THE FUEL SYSTEM IS UNDER A CONSTANT PRESSURE (EVEN WITH THE ENGINE OFF). BEFORE SERVICING ANY FUEL SYSTEM HOSES, FITTINGS OR LINES, THE FUEL SYSTEM PRESSURE MUST BE RELEASED. REFER TO THE FUEL SYSTEM PRESSURE RELEASE PROCEDURE.
Inspect all hose connections such as clamps, couplings and fittings to make sure they are secure and leaks are not present. The component should be replaced immediately if there is any evidence of degradation that could result in failure.
Never attempt to repair a plastic fuel line/tube. Replace as necessary.
Avoid contact of any fuel tubes/hoses with other vehicle components that could cause abrasions or scuffing. Be sure that the plastic fuel lines/tubes are properly routed to prevent pinching and to avoid heat sources.
The lines/tubes/hoses used on fuel injected vehicles are of a special construction. This is due to the higher fuel pressures and the possibility of contaminated fuel in this system. If it is necessary to replace these lines/tubes/hoses, only those marked EFM/EFI may be used.
If equipped: The hose clamps used to secure rubber hoses on fuel injected vehicles are of a special rolled edge construction. This construction is used to prevent the edge of the clamp from cutting into the hose. Only these rolled edge type clamps may be used in this system. All other types of clamps may cut into the hoses and cause high-pressure fuel leaks.
Use new original equipment type hose clamps. Tighten hose clamps to 3 Nm (25 in. lbs.) torque.