Electronic fuel injection diesel engines usually require exhaust operation when refueling without fuel. This is because when the diesel engine runs out of fuel for a long time or the fuel level is severely insufficient, air in the fuel system may enter, causing poor fuel supply or inability to start. The main purpose of exhaust operation is to remove air from the fuel system and ensure that fuel can be smoothly supplied to the engine.

　　The specific steps of exhaust operation may vary depending on the vehicle model and engine model, but generally include the following steps:

1. Preliminary inspection: Confirm that the switch of the fuel tank has been turned on and check the fuel level in the tank. If insufficient fuel is found, sufficient diesel should be added first.

　　2. Diesel filter exhaust: Press the pump oil handle on the fuel transfer pump and observe the loosened air release screw. At the beginning, there may be bubbles in the discharged fuel. At this time, the pump handle should be continuously pressed until the discharged fuel no longer contains bubbles.

　　3. Low pressure oil passage exhaust of fuel injection pump: Place the ignition switch in the ON position (note not starting the engine), and the fuel cut-off solenoid valve will be in the open state at this time. Then, loosen the bleed screw on the fuel injection pump and perform the exhaust operation.

　　4. High pressure oil circuit exhaust: For high-pressure common rail electronic fuel injection diesel engines, specific methods (such as high-pressure common rail exhaust air method) may be required to eliminate air from the high-pressure oil circuit. This usually involves finding the return pipe on the fuel tank and performing corresponding operations.

　　5. Check and confirm: After completing the above steps, check for any leaks in the fuel system and confirm that the engine can start and run normally.

　　It should be noted that when performing exhaust operations, it is necessary to strictly follow the vehicle manual or professional guidance to avoid malfunctions or damage caused by improper operation. In addition, if the diesel engine has not been used or maintained properly for a long time, other related inspections and maintenance work may be required.

　　In general, when refueling an electronic fuel injection diesel engine without fuel, it is necessary to perform exhaust operations to ensure the normal operation of the fuel system and the smooth start of the engine.