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.
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.
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). |
An injector balance test is performed with the scan tool. This test will properly identify a stuck closed or a noisy injector nozzle. Typically, a nozzle failure will fall into this criteria.
If a suspect nozzle has been located, the nozzle can be swapped with the adjacent cylinder. The balance test can be repeated as a check in order to positively identify a malfunctioning nozzle.
Caution: Do not place your hands or arms near the tip of the nozzle when testing the nozzles. The high pressure atomized fuel spray from a nozzle has sufficient penetrating power to puncture flesh and destroy tissue. This may result in blood poisoning. Always enclose the nozzle tip in a receptacle, preferably transparent, in order to contain the spray.
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.
Important: Each test should be considered independent of the others (for example, when checking the opening pressure, do not check for leakage). If all of the following tests are satisfied, the nozzle assembly can be reused. If any one of the tests is not satisfied, the complete nozzle assembly must be replaced. When performing the injection nozzle tests, refer to the instructions provided with the nozzle tester J 29075- B.
• | Position a nozzle tester on a workbench. |
• | Install one nozzle on the tester fitting. |
• | Place a container under the nozzle that will deflect the nozzle spray and absorb the test fluid. |
• | Connect the two clear plastic hoses (1 inch long) over the leak-off fittings. |
• | Close the shutoff valve at the pressure gauge. |
• | Operate the lever of the nozzle tester repeatedly and briskly in order to fill and flush the nozzle with test oil. |
Caution: When testing nozzles, do not place your hands or arms near the tip of the nozzle. The high pressure atomized fuel spray from a nozzle has sufficient penetrating power to puncture flesh and destroy tissue and may result in blood poisoning. The nozzle tip should always be enclosed in a receptacle, preferably transparent, to contain the spray.
Important: The Injector Nozzle Opening Pressure and Leakage tests should be performed only on nozzles with high mileage, engines that have been over heated or on vehicles that pull heavy loads. False or inaccurate readings can occur if the following tests are not performed to the above criteria.