Operation CHARM: Car repair manuals for everyone.

Injection Nozzle Test

If an injection nozzle is not properly delivering fuel into the pre-combustion chamber of a cylinder, driveability could be greatly effected, or a DTC could be set. If other diagnosis indicates, or if the injection nozzles are suspected of not properly delivering fuel, they should be tested. Typically, a nozzle failure can be detected by using the injector balance test. Nozzle testing is comprised of the following checks:

- The injector balance test (performed with scan tool).
- The nozzle opening pressure (see Important statement).
- Leakage (see Important statement).

Important: The Injector Nozzle Opening Pressure and Leakage tests should be performed only on vehicles with high mileage, engines that have been over heated, or vehicles that pull heavy loads. False or inaccurate readings can occur if the following tests are not performed to the above criteria.