12. Monitor The Fuel Rail Pressure (FRP) While Cranking Test
12. MONITOR THE FUEL RAIL PRESSURE (FRP) WHILE CRANKING TESTPurpose:
The purpose of this test is to determine if the high pressure fuel system generates minimum fuel pressure to sustain starting.
Scan Tool - Data List Monitoring
- The scan tool may reset below 9.5 volts.
- Select the parameters indicated from the scan tool parameter list and monitor while cranking the engine.
A reading below the specification indicates low fuel rail pressure during crank.
Check the fuel rails and high pressure fuel lines for leaks.
Recommended Procedure:
- Connect the scan tool.
- Key ON, engine OFF.
- Access and monitor the FRP volts PID while cranking the engine.
Fuel pressure below 27.58 MPa (4,000 psi) indicates that the fuel pressure is too low to sustain engine starting. Check the high pressure fuel injection pump, high pressure fuel supply line to the fuel rails and left and right bank fuel rails for leaks. If no leaks are present GO to Pinpoint Test ME and diagnose the high pressure fuel injection pump. Tests ME: Fuel Pump Control - High Pressure Fuel Injection Pump
Possible Causes:
- High pressure fuel injection pump
- Fuel volume control valve or circuitry
- Fuel pressure control valve or circuitry
- Fuel injectors
Tools Required:
Scan tool