Crossfire SRT-6 V6-3.2L SC VIN N (2005)
Fuel Pressure: Testing and Inspection
Fuel Pressure Leak Down Test
FUEL PRESSURE LEAK DOWN TEST
CHECK VALVE OPERATION
The electric fuel pump outlet contains a one-way check valve to prevent fuel flow back into the tank, and to maintain fuel supply line pressure (engine
warm) when the pump is not operational. It also is used to keep the fuel supply line full of gasoline when the pump is not operational. After 30 minutes
the fuel pressure may drop to 2.5 bar (36 psi), but the liquid gasoline will remain in the fuel supply line between the check valve and fuel injectors.
When the fuel pump is activated, the fuel pressure should immediately (1-2 seconds) rise to specification.
Abnormally long periods of cranking to restart a hot engine that has been shut down for a short period of time may be caused by either fuel pressure
bleeding past a fuel injector(s), or fuel pressure bleeding past the check valve in the fuel pump. To determine the cause of this condition:
1. Remove the engine cover for access and disconnect the fuel inlet line at the fuel rail.
2. Connect the correct fuel line pressure test adapter tool between the disconnected fuel inlet line and fuel rail.
3. Connect Special Tool C-4799-B or equivalent to the test port on the test adapter tool.
4. Start the engine and bring to normal operating temperature.
5. Observe the test gauge. Normal operating pressure should be 3.7 - 4.1 bar (54 - 60 psi).
6. Shut engine off.
7. Pressure should not fall below 2.5 bar (36 psi) after 30 minutes.
8. If pressure falls below 2.5 bar (36 psi) within 30 minutes, it must be determined if a fuel injector, the check valve within the fuel pump, or a fuel
tube/line is leaking.
9. Again, start the engine. After bringing to normal operating temperature, shut engine off.
TESTING FOR FUEL INJECTOR OR FUEL RAIL LEAKAGE
Clamp off the rubber hose portion of the adaptor tool between the fuel rail and the test port T . If the pressure now holds at or above 2.5 bar (36 psi) for
30 minutes, a fuel injector or the fuel rail is leaking.
TESTING FOR FUEL PUMP CHECK VALVE, FILTER/REGULATOR CHECK VALVE, OR FUEL TUBE/LINE LEAKAGE
Clamp off the rubber hose portion of the adaptor tool between the vehicle fuel line and the test port T . If the pressure now holds at or above 2.5 bar (36
psi) for 30 minutes, a leak may be found in the fuel tubes or lines or one of the check valves. Note: A quick loss of pressure usually indicates a defective
check valve in the pressure regulator. A slow loss of pressure usually indicates a defective check valve in the fuel pump. These valves are not serviced
separately. If found defective, the entire component that the valve is a part of must be replaced as an assembly.
