Testing

1. Remove nozzles from engine and clean outside of injector. Clean the center hole with a cleaning needle. If the center hole is plugged, replace the injector.
2. Install a nozzle onto the tester. Close the pressure gauge valve on the tester and make sure that the discharge line valve handle is in a vertical position. Depress the pump lever rapidly (equivalent to 6-8 strokes per second) to bleed the system.
3. Depress pump lever with short, fast partial strokes (equivalent to 4-6 strokes per second).
4. The spray pattern should be uniform and well atomized. If it is not, replace the injector.
NOTE: This test procedure (step #5) also applies to new injection nozzles.
5. Turn the discharge line valve handle to a horizontal position. Depress the pump lever slowly and uniformily. Return the discharge line valve handle on valve in test line to vertical position. A well defined, vertical cord-like jet should come out of the center hole. If it does not, replace the injector.
6. A new injection nozzle should have a soft chatter at lever speeds of 1-2 strokes per second. If a new nozzle does not chatter, replace the injector.
Note: Used injection nozzles should not be evaluated for chatter at lower speeds. A used nozzle can generally be used if it passes the Opening Pressure Test, Leakage Test, and Spray Pattern Test.
7. Open pressure gauge valve on tester. Depress pump lever slowly (1 stroke per second) and read the opening pressure (the pressure when the nozzle opens and the jet starts). The opening pressure should be 135 to 143 bar (1958 to 2074 psi) for a new nozzle, and 1740 bar (120 psi) for a used nozzle. If the nozzle does not meet these specifications, replace the injector.
8. Depress pump lever until the pressure gauge reads 20 bar (290 psi) below the opening pressure. No drop should fall from the nozzle within 10 seconds. If the nozzle does not meet these specifications, replace the injector.