NOTE: This test is not effective on a cold engine, less than 21°C [70°F] coolant temperature, or with a loose overhead setting.

Install an isolated fuel supply tank to the inlet and drain lines. Add fluorescent tracer, Part Number 3376891, to the fuel supply tank.

Remove the valve cover mounting hardware but do not remove the valve cover.

Start the engine and operate it at high idle for 30 seconds. Let the engine go to low idle.

Complete the next step within 5 minutes.

While the engine is operating at low idle, remove the valve cover. Refer to Procedure 003-011 in Section 3.

Use black light, Part Numbers 3377253 or 3377394, to find fuel leaks from inside or around the injector. Refer to the OEM service manual.

NOTE: Injectors normally have a small amount of fuel leakage.

If there is excess leakage around the outside of the injector, check the top o-ring for damage.

Remove the injector and replace all three o-rings. Refer to Procedure 006-026 in Section 6.

If there is excess leakage from inside the injector, replace the injector. Refer to Procedure 006-026 in Section 6.

Remove the fuel drain line from the fuel drain tee fitting. Install a cap on the tee fitting.

Remove the fuel drain line from the gear pump check valve. Install a plug in the fuel line.

Remove the fuel supply line from the fuel supply pump shutoff valve.

Install a regulated air supply to the fuel supply line.

Apply air pressure to the cylinder head. The maximum air pressure is 552 kPa [80 psi].

Check for fuel leaks at each injector.

NOTE: A little engine oil is helpful to expose fuel leaks. Some leaks can be heard.

Replace the leaking injector or replace all three outer o-rings. Refer to Procedure 006-026 in Section 6.

Check the injector for normal leakage.

Remove the air line and install the fuel supply line.

Remove the plug from the gear pump drain line.

Install the drain line on the gear pump check valve.

Remove the cap from the fuel drain line fitting.

Install the fuel drain line.