23. Inverse Fuel Injector Leak Test

23. INVERSE FUEL INJECTOR LEAK TEST

Purpose:

WARNING:
- Contact with exposed fuel injector wiring, if energized, may result in electric shock. Use care when working on or around energized fuel injector wiring. Fuel injector wiring supplies high voltage to operate the fuel injectors. Failure to follow this instruction may result in serious personal injury.
- Before working on or disconnecting any of the fuel tubes or fuel system components, relieve the fuel system pressure to prevent accidental spraying of fuel. Fuel in the fuel system remains under high pressure, even when the engine is not running. Failure to follow this instruction may result in serious personal injury.

NOTICE: If the fuel system is not bled, a fuel injector may be incorrectly diagnosed.

The purpose of this test is to check for leaks from the fuel injector at the nozzle or the return port.

Inverse Fuel Injector Leak Test

NOTE: Additional DTCs may result during this procedure.

- Carry out the Inverse Fuel Injector Leak Test.







- Ignition in the OFF position.
- Remove the right hand and left hand valve covers.
- Release the fuel pressure. Refer to the Fuel Delivery and Air Induction Fuel System, for the Fuel System Pressure Release - Diesel Engine procedure.
- Disconnect the 15-pin inline connector on the left hand valve cover harness.
- Disconnect the 15-pin inline connector on the right hand valve cover harness.
- Disconnect all the fuel injector connectors. Refer to the Fuel Delivery and Air Induction, Fuel Charging and Controls.
- Remove all the fuel injector supply tubes, fuel injector hold down clamp assemblies and the fuel injectors.
- Assemble all fuel injectors except the cylinder number 1 fuel injector to the fuel rail using the original fuel injector supply tubes. Position the fuel injectors so the fuel nozzle and drain hole are visible.
- Connect the open end of the hose from the Air Purge Adapter 310-184 to the fuel injector supply tube, put the other end of the hose in a fuel container and crank the engine for 15 seconds. Attach the cylinder number 1 fuel injector to the fuel injector supply tube with the fuel injector positioned so the fuel nozzle and drain hole are visible.
- Disconnect the cylinder number 2 fuel injector from the fuel injector supply tube and put the other open end of the tube in a fuel container and crank the engine for 15 seconds. Attach the cylinder number 2 fuel injector to the fuel injector supply tube with the fuel injector positioned so the fuel nozzle and drain hole are visible. This must be done or a leaking fuel injector may not be detected.
- Install the Fuel Injector Cups 303-1261 or equivalent to the fuel injectors to contain any side spray from the fuel nozzles.
- Ignition ON, engine OFF.
- Crank the engine for 10 seconds. Check for fuel injectors that are leaking fuel from the fuel nozzles or drain holes.
- Ignition in the OFF position.
- Install a new fuel injector for any identified fuel injectors that are leaking fuel from the fuel nozzles or drain holes.
- Remove the Fuel Injector Cups 303-1261 or equivalent from the ends of the fuel injectors.
- Install all the fuel injectors. Install new fuel injector supply tubes, O-rings and combustion washers for all fuel injectors that were removed.
- Reassemble the engine.
- Bleed the high pressure fuel system. Refer to the Fuel Delivery and Air Induction Fuel System for the Fuel System Bleeding - High Pressure, Diesel Engine procedure.
- For a no start condition with no leaks present and the engine oil level is correct, carry out the Monitor FRP Sensor No Start Test to continue diagnosis. 20. Monitor FRP Sensor No Start Test
- For a hard start condition with no leaks present and the engine oil level is correct, check for electrical harness chafes. GO to Pinpoint Test ME. Test ME: Fuel Pump Control - High Pressure Fuel Injection Pump
- If entering this test from pinpoint test AB, no leaks are present and the engine oil level did not increase, there is no fuel system concern. Refer to Symptom Charts, No Diagnostic Trouble Codes (DTCs) Present Symptom Chart Index and follow the diagnosis for Exhaust System Concerns. No Diagnostic Trouble Codes (DTCs) Present Symptom Chart Index
- It no leaks are present and the engine oil level increased when carrying out the High Pressure Fuel System Test and Fuel System Leak Test, install a new high pressure fuel injection pump. Clear the fuel injector adaptive tables using the scan tool.

Possible Causes:
- Damaged fuel injector
- Leaking fuel injector nozzle or fuel injector
- Fuel lines
- Fuel rail

Tools Required:
- Scan tool
- Air Purge Adapter 310-184
- Fuel Injector Cups 303-1261 or equivalent