Functional Description - Fuel Pump Assembly
The fuel pump assembly is mounted inside the fuel tank and contains the following components:
- Mounting flange
- Electric fuel pump
- Fuel pump reservoir
- Inlet strainer
- Fuel pressure regulator
- Fuel level sending unit
- Fuel filter
The electric fuel pump is located within the fuel pump assembly, inside the reservoir. The electric fuel pump is a positive displacement, immersible pump with a permanent magnet electric motor. The fuel pump activation is managed by the Powertrain Control Module (PCM). On vehicles equipped with a Fuel Pump Control Module (FPCM), the PCM commands pump operation to the FPCM and the FPCM directly controls the power supply to the fuel pump. Read the FPCM functional description for more details on the operating relationship. The table below shows the fuel system pressure specifications for all applications during normal operation.
| VARIABLE FUEL PRESSURE SYSTEM SPECIFICATIONS (6.2L ENGINES) | ||
| CRANKING | 520 kPa (75.4 psi) | System operates in open loop during cranking |
| IDLE | 340 - 400 kPa (49 - 58 psi) | Normal operating range at idle - Pressure is dependant on ambient and fuel temp. Pressure is raised during high temp to prevent boiling |
| NORMAL RANGE OF OPERATION | 340 - 550 kPa (49 - 80 psi) | Normal operating range between idle and high engine demand |
| 100% DUTY CYCLE | 600 - 700 kPa (87 - 101.5 psi) | This is regulated by the pressure relief valve in the Fuel Pump. The pressure can vary from pump to pump. |
| 4 CYLINDER (1.0L/1.3L GSET / 2.0L GMET ENGINES) | ||
| CRANKING | 580 kPa (84.1 psi) | System operates in open loop during cranking |
| ALL OTHER OPERATING CONDITIONS | 520 kPa (75.4 psi) | The fixed pressure systems should maintain approximately 75.0 psi during normal operation |
| 6 CYLINDER (3.0L GMET ENGINES) | ||
| CRANKING | 650 - 660 kPa (94.2 - 95.7psi) | System operates in open loop during cranking |
| ALL OTHER OPERATING CONDITIONS | 600 kPa (87 psi) | The fixed pressure systems should maintain approximately 87 psi during normal operation. Periodically, with the engine @ idle, the pressure is bumped up to 650 - 660 kPa (94.2 - 95.7psi) to check for a stuck fuel rail pressure sensor signal. |
| FIXED PRESSURE SYSTEM SPECIFICATIONS (GMET4 2.0L EVO) | ||
| The fixed pressure systems should maintain approximately 662 kPa (96.0) psi during normal operation | ||
| FIXED PRESSURE SYSTEM SPECIFICATIONS (ALL OTHER ENGINES) | ||
| The fixed pressure systems should maintain approximately 400 kPa (58.0) psi during normal operation | ||