Contents: 1st method ↓ 2nd method ↓
1st method
When fuel is supplied under pressure from the high-pressure fuel pump to the injector, the injection pressure changes between the start of injection and the end of injection. This pressure change is manifested in the vibration of the injector needle valve if the injector is in good condition. When checking the valve on a special device, a characteristic vibrating sound should be heard. Checking for needle valve vibration is performed as follows. Clean the injectors. Connect the injector to the device with a pressure gauge for checking the injection pressure (Fig. 3-45). Create injection pressure by evenly pumping the handle of the pump of the device. Open the pressure gauge valve. When fuel flows out of the injector, a uniform vibrating sound should be heard. An uneven vibrating sound or its absence indicates a malfunction of the atomizer or sticking of the injector needle valve. In this case, replace the injector.
2nd method
Clean the injector. Dip the valve needle into clean oil and push it into the injector body until it stops, then pull it out ⅔ of the way.
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Release the needle, which should fall onto the saddle under its own weight.
If the needle does not drop, replace the injector assembly.
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