Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

Verify the following conditions do not exist:
NOTE: It may be necessary to remove engine components for the visual inspections.
- Hoses and lines that are flattening when the engine is running or have kinks that would restrict the flow of fuel
- Fuel leaks between the fuel tank and the fuel injection pump
- Fuel leaks in the fuel return lines
  NOTE: A fuel return line that is leaking, is a good indication there is a restriction in the return system.
- If any leaks or restrictions are present
  Repair as necessary
- No leaks or restrictions are present
Disconnect the supply hose at the G18 High Pressure Fuel Pump.
Connect the J-37287 Fuel Line Shut-off Adapter to the supply hose and place the other end of the hose into a suitable container.
Ignition ON.
Command the fuel pump on for 30 s
Verify at least 1200 mL (40.2 oz) of fuel is in the container.
- If less than 1200 mL (40.2 oz)
1. Verify that the fuel filter is not restricted.
  - If the fuel filter is restricted, replace fuel filter.
  - If the fuel filter is not restricted, Replace the G12 Fuel Pump assembly.
- If greater than 1200 mL (40.2 oz)
Reconnect the supply hose at the G18 High Pressure Fuel Pump.
Verify the engine will start and run.
- If the engine cranks but does not run
  Refer to Fuel Pressure Regulator Diagnosis .
- If the engine will start and run
Engine running, verify with a scan tool than the Fuel Rail Pressure Sensor and Desired Fuel Rail Pressure parameters closely match.
- If the Fuel Rail Pressure parameters do not closely match
  Refer to Fuel Pressure Regulator Diagnosis .
- If the Fuel Rail Pressure parameters closely match
All OK