Fuel System

FUEL SYSTEM

Overview
The fuel system supplies the sequential multi-port fuel injection (SF1) fuel injectors with clean fuel at a controlled pressure. The powertrain control module (PCM) controls the fuel pump and monitors the fuel pump monitor (FPM) circuit. The PCM controls the fuel injector on/off cycle duration and determines the correct timing and amount of fuel delivered. If the injectors have been replaced it is necessary to clear the learned values contained in the keep alive memory (KAM) in the PCM. For more information, refer to Diagnostic Methods, Resetting The Keep Alive Memory (KAM). Resetting The Keep Alive Memory (KAM)

Electronic Returnless Fuel System

Electronic Returnless Fuel System:

The hybrid vehicle uses the electronic returnless fuel system. The system consists of a fuel tank with reservoir, the fuel pump, the fuel filter, the fuel supply line, the fuel rail pressure temperature (FRPT) sensor, the fuel rail, the fuel pump driver module (FPDM), and the fuel injectors. For additional information on the fuel system components, refer to Engine Control Components. Engine Control Components

Operation of the system is as follows:
1. The fuel delivery system is enabled during crank or running mode once the PCM receives a crankshaft position (CKP) sensor signal.
2. The fuel pump logic is defined in the fuel system control strategy and is executed by the PCM.
3. The PCM commands a duty cycle to the FPDM.
4. The FPDM modulates the voltage to the fuel pump required to achieve the proper fuel pressure. Voltage for the fuel pump is supplied by the FPDM.
5. The FRPT sensor provides the PCM with the current fuel rail pressure and temperature. The PCM uses this information to vary the duty cycle output to the FPDM to compensate for varying loads.
6. The fuel injector is a solenoid operated valve that meters the fuel flow to each combustion cylinder. The fuel injector is opened and closed a specific number of times per crankshaft revolution. The amount of fuel is controlled by the length of time the fuel injector is held open. The injector is normally closed and is operated by VPWR from the power relay. The ground signal is controlled by the PCM.
7. There are 3 filtering or screening devices in the fuel delivery system. The intake sock is a fine, nylon mesh screen mounted on the intake side of the fuel pump. There is a fuel filter screen located at the fuel rail side of the fuel injector. The fuel filter assembly is located between the fuel pump and the fuel rail.
8. The fuel pump module is a device that contains the fuel pump and the fuel sender assembly. The fuel pump is located inside the reservoir and supplies fuel through the fuel pump module manifold to the engine and the fuel pump module jet pump.
9. The front inertia fuel shut-off (IFS) switch is used to de-energize the fuel delivery secondary circuit in the event of a collision. The IFS switch is a safety device that should be reset only after a thorough inspection of the vehicle following a collision.

Fuel Pump Control

FP Duty Cycle Output From PCM (Part 1):

FP Duty Cycle Output From PCM (Part 2):

The fuel pump (FP) signal is a duty cycle command sent from the PCM to the FPDM. The FPDM uses the FP command to operate the fuel pump at the speed requested by the PCM or to turn the pump off.

For additional information, refer to Powertrain Control Hardware, Fuel Pump Driver Module (FPDM). Powertrain Control Hardware

Fuel Pump Monitor (FPM)

Fuel Pump Driver Module (FPDM) Duty Cycle Signals:

The FPDM communicates diagnostic information to the PCM through the FPM circuit. This information is sent by the FPDM as a duty cycle signal. The 3 duty cycle signals that may be sent are listed in the table.

Fuel Filters
The system contains 3 filtering or screening devices. Refer to the individual component illustrations for locations.
1. The fuel intake sock or screen is a fine nylon mesh sock mounted on the intake side of the fuel pump. It is part of the assembly and cannot be repaired separately.
2. The filter/screen at the fuel rail port of the injectors is part of the fuel injector assembly and cannot be repaired separately.
3. The fuel filter assembly is located between the fuel pump (tank) and the fuel rail. A new filter may be installed.