Pic. 3.14. Location of the injector and glow plug in the pre-combustion chamber 1 - nozzle; 2 - nozzle assembly with sprayer; 3 - sealing ring of the injector in the cylinder head; 4 - flameproof washer; 5 - protective cap of the sprayer
- Remove the injector body.
- Secure the nozzle body in a vice, the jaws of which are covered with soft material.
- Disassemble the injector body and remove all parts, placing them in the order of removal.
Attention. The needle and nozzle body are matched in pairs with high precision. This precision processing requires careful handling. those. It is not recommended to handle them with hands that contain traces of oil, fuel or caustic substances, as this will lead to microscopic corrosion of their surfaces.
- Check the condition of the injector parts.
- Reassemble the injector in the reverse order of disassembly.
- Install the injector onto the cylinder head.
Visual inspection
Visually check the injector for the following defects:
- deformation of the needle locking seat or presence of roughness on its surface;
- wear or damage to the fuel injection channel;
- parallel marks or depressed marks on the needle;
- traces of cavitation on the needle;
- ovality of the fuel injection channel;
- excessive heating of the nozzle body;
- nozzle wear.
If there are defects or damage to parts, replace the nozzle.
Needle movement analysis
- Clean the diesel fuel injector parts.
- Dip the needle into clean oil and insert it into the injector body.
- Pull the needle out of the nozzle body 2/3 of the way.
- Release the needle; it should move back into place; otherwise, replace the nozzle.
Checking injection pressure
Attention. When checking the operation of fuel injectors, never place your hands or any part of your body under the stream of fuel coming out of the injector. Fuel exits the injector under high pressure and can penetrate the body through the skin, causing serious injury.
- Install the injector onto the test pump.
- Create pressure with the pump and determine the opening pressure of the nozzle.
- If the nozzle opening pressure does not meet the required pressure, correct it by replacing the adjusting washers in the nozzle body.
Leak test
- Install the injector on the test pump
- Create a pressure of 120 bar and maintain it for 30 s, while no fuel should leak from under the needle.
Note. On vehicles with G8T 714 engines, the opening pressure of the injector with a needle movement sensor is not adjustable. If the pressure differs by more than 8 bar. replace the injector.