Fuel Delivery System
FUEL DELIVERYThe front wheel drive car uses a plastic fuel tank located rear center of the vehicle.
The Fuel Delivery System consists of: the following items:
- Electric fuel pump module
- Fuel filter
- Tubes/lines/hoses
- 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 replaceable, it is mounted on the outside and on top of the fuel tank. Refer to the Maintenance Schedules in the Introduction for recommended fuel filter replacement intervals.
FFV Replacement Parts
Many components in a Flexible Fuel Vehicle (FFV) are designed to be compatible with ethanol. Always be sure that the vehicle is serviced with correct ethanol compatible parts.
CAUTION: Replacing fuel system components with non-ethanol compatible components can damage your vehicle and may void the warranty.
The fuel system is provided fuel pressure by an in-tank pump module. The PCM controls the operation of the fuel system by providing battery voltage to the fuel pump through the fuel pump relay. The PCM requires only three inputs and a good ground to operate the fuel pump relay. The three inputs are:
- Ignition voltage
- Crankshaft Position (CKP) sensor
- Camshaft Position (CMP) sensor
FUEL FILTER
Fig. 1 Side View - Filter/Regulator:
Fuel Filter/Fuel Pressure Regulator
A combination fuel filter and fuel pressure regulator is used on all gas powered engines. It is located on the top of the fuel pump module.
It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter is also part of the assembly.
Fuel Pressure Regulator Operation
The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of approximately 400 kPa ±34 kpa (58 psi ±5 psi.) at the fuel injectors.
Fuel is supplied to the filter/regulator by the electric fuel pump through an opening tube at the bottom of filter/regulator.
The fuel pump module contains a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine.
If fuel pressure at the pressure regulator exceeds approximately 58 psi, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. A separate fuel return line is not used with any gas powered engine.
FUEL LEVEL SENDING UNIT / SENSOR
The fuel gauge sending unit (fuel level sensor) is attached to the side of the fuel pump module. The sending unit consists of a float, an arm, and a variable resistor (track). The resistor track is used to send electrical signals to the instrument cluster for fuel gauge operation and are then transmitted to the engine controller for OBDII emission requirements.
For Fuel Gauge Operation
As fuel level increases, the float and arm move up. This increases the sending unit resistance, causing the fuel gauge to read full. As fuel level decreases, the float and arm move down. This decreases the sending unit resistance causing the fuel gauge to read empty.
After this fuel level signal is sent to the instrument cluster, the instrument cluster will transmit the data across the J1850 bus circuits to the PCM.
For OBD II Emission Requirements
The voltage signal is sent to the instrument cluster to indicate fuel level. The cluster transmits the fuel level to the PCM where it is used to prevent a false setting of misfire and fuel system monitor trouble codes. This occurs if the fuel level in the tank is less than approximately 15 percent of its rated capacity.
FUEL LINES
Fuel Lines/Hoses and Clamps
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.
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.
FUEL PRESSURE REGULATOR
A combination fuel filter and fuel pressure regulator is used on all gas powered engines. It is located on the top of the fuel pump module.
Fig. 8 Side View - Filter/Regulator:
It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter (Fig. 8) is also part of the assembly.
Fuel Pressure Regulator Operation
The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of approximately 400 kpa ±34 kPa (58 psi ±5 psi.) at the fuel injectors.
Fuel is supplied to the filter/regulator by the electric fuel pump through an opening tube at the bottom of filter/regulator (Fig. 1).
The fuel pump module contains a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine.
If fuel pressure at the pressure regulator exceeds approximately 58 psi, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. A separate fuel return line is not used with any gas powered engine.
FUEL PUMP
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. The fuel pump module is suspended in fuel in the fuel tank.
The pump draws fuel through a strainer and pushes it through the motor to the outlet. The pump contains a check valve. The 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 dead-headed pressure output of approximately 880 kPa (130 psi). The regulator adjusts fuel system pressure to approximately 400 kpa ±34 kpa (58 psi ±5 psi).
FUEL PUMP MODULE
Fig. 11 Fuel Pump Module:
The fuel pump module is installed in the fuel tank (Fig. 11).
The fuel pump module contains the following:
- Electric fuel pump
- Fuel pump reservoir
- Inlet strainer
- Fuel filter/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 requires service, replace the fuel pump module.
FUEL RAIL
Fig. 15 Fuel Rail:
The fuel rail supplies the necessary fuel to each individual fuel injector and is mounted to the intake manifold (Fig. 15).
The fuel pressure regulator is no longer mounted to the fuel rail on any engine. It is now located on the fuel tank mounted fuel pump module. Refer to Fuel Filter/Fuel Pressure Regulator in the Fuel Delivery System for information. The fuel rail is not repairable.
FUEL TANK
The fuel tank is constructed of a plastic material. Its main functions are for fuel storage and for placement of the fuel pump module. The tank is made from High density Polyethylene (HDPE) material. If equipped with ORVR (Onboard Refueling Vapor Recovery) it has been added to the fuel tank to control refueling vapor emissions.
All models pass a full 360 degree rollover test without fuel leakage. To accomplish this, fuel and vapor flow controls are required for all fuel tank connections.
All models are equipped with either one or two rollover valves mounted into the top of the fuel tank (or pump module).
An evaporation control system is connected to the rollover valve(s)/control valves to reduce emissions of fuel vapors into the atmosphere. When fuel evaporates from the fuel tank, vapors pass through vent hoses or tubes to a charcoal canister where they are temporarily held. When the engine is running, the vapors are drawn into the intake manifold. In addition, fuel vapors produced during vehicle refueling are allowed to pass through the vent hoses/tubes to the charcoal canister(s) for temporary storage (prior to being drawn into the intake manifold). All models are equipped with a self-diagnosing system using a Leak Detection Pump (LDP). Refer to the Emission Control System for additional information.
Inlet Check Valve
All vehicles have an inlet check valve on the inside of the fuel tank at the filler inlet
The valve prevents fuel from splashing back on customer during vehicle refueling. The valve is a non-serviceable item.
ROLLOVER VALVE
All vehicles have rollover valve(s) on top of the fuel tank.
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.