Checking Fuel Injector Leakage Rate

Injector rail must be removed from engine. Refer to appropriate repair manual and flat rate manual for further information.

1. Remove retaining clips and pull fuel injectors out of injector rail.

Install injectors in cylinder order (1-6) into the injector test rail and secure them with the retaining clips.

2. Plug test wire harness connectors onto injectors.

3. Connect air hose (using the appropriate quick disconnect fitting) to the regulator/gauge assembly. No liquids, i.e., oil, water, etc. should be present in compressed air supply.

Caution: The air pressure regulator knob (see aftached illustration) must be turned out (counterclockwise) to its stop. This will prevent maximum air flow to the injectors, while they are in the closed position, when the air supply is connected.
4. To remove any residual fuel from the injectors, connect the test wire harness leads to a 12V power supply (injectors open) and turn the air pressure regulator knob in (clockwise) until the maximum air pressure is reached on the gauge. Continue to blow air through for 2 minutes at this pressure. Failure to perform this step will lead to incorrect results while performing the air leakage rate test.

Warning: Injector tips should be covered/shielded, i.e., with a clean shop rag to prevent any residual fuel in the injectors from spraying freely into the atmosphere.

5. Regulate air pressure down to zero pressure using knob on regulator.

6. Disconnect power source from injectors (injectors closed).

7. Regulate air pressure up to the nominal fuel pressure value for the engine under test. See appropriate Technical Data microfiche.

8. Place the injector test rail in the water container supplied. For proper leakage readings, the injector tips must be pointed straight down into the water container and submerged up to the lower "O" ring on the injector body.

Note: Only clean tap water at room temperature should be used for testing injectors.

9. Observe air bubbles escaping from the injector tips. The maximum permissible air leakage rate is 2 bubbles per injector in 20 seconds.

10. Note which injectors have an air leakage rate greater than 2 bubbles in 20 seconds.

11. Remove the injector test rail from the water container.

12. Regulate air pressure down to zero pressure.

13. Connect the test wire harness to a 12V power supply (injectors open). Regulate air pressure to the maximum air pressure reading on the gauge and blow through injectors for 2 minutes.

Note: Any injectors which are not blown through with compressed air for at least 2 minutes after the Checking procedure will be subject to corrosion of the injector tip. Warranty claims for injectors with traces of such corrosion will not be accepted.

14. Regulate air pressure back to zero bar and disconnect 12V power supply.
15. Remove all injectors from the test rail.

16. Replace the necessary injectors (if any) which are noted in Step 10 with new injectors. Reinstall all injectors on the engine's fuel rail.

Reinstall fuel rail with injectors on engine as per repair manual.

Run engine briefly to positively remove any remnants of water from the injectors.

Important
Note: There is no need to test new injectors before installation.

New injectors are treated with a preserving agent by the manufacturer which dissolves after approximately 5 minutes of continuous engine operation.