Nozzle Opening Pressure Test

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:
^ Injector Nozzle Opening Pressure and Leakage tests should only be performed on vehicles 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.
^ Each test should be considered independent of the others (for example, when checking 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.
^ Install two clear plastic hoses (1 in. long) over the leak-off fittings.
^ Close the shutoff valve at the pressure gauge.
^ Operate the lever of the nozzle tester repeatedly and briskly to fill and flush the nozzle with test oil.

1. Open the shutoff valve at the pressure gage one-quarter turn.
2. Depress the tester lever slowly. Note at what pressure the needle of the pressure gage stopped. The maximum observed pressure is the opening pressure. Some nozzles may pop while other nozzles may drip down (this is not leakage).
3. The opening pressure should not fall below the lower limit of 105 bar (1500 psi) for naturally aspirated engines and 117 bar (1700 psi) for turbo-charged engines for used nozzles.
4. Replace nozzles which fall below the lower limit.