The main reason for causing excavator heavy-duty flameout is: Since the working pump displacement is too large, the engine is automatically turned off due to heavy load. According to the hydraulic system map, it should first control the servo piston to find the working pump displacement, and then investigate according to complexity according to the function of each control valve.
You can first look at whether the LS-EPC solenoid valve, the connection between the PC-EPC solenoid valve is reversed. If the line is reversed, the signal transmission error of the pump controller is caused, and the machine is lost due to the replacement of the pump. Control and cause the engine to turn off. If there is no error, then detect the working condition of the PC EPC solenoid valve, its main technical indicator is that the electric resistance of the PC-EPC solenoid valve coil should be 7 to 14 ohms. If the PC-EPC solenoid valve is damaged, the machine is in the heavy duty operation. The valve is unable to receive a command to reduce the pump displacement of the pump controller, so that the PC-EPC solenoid valve cannot be adjusted to the displacement of the pump, and the engine is turned off due to the load.
Such as the solenoid valve is not faulty, then check the pressure control valve (PC valve), the PC valve action is that when the change in the external load is changed to the working pressure, the PC valve senses the change, and then according to the pump and the engine "" The best matching "principle, automatically adjusts the displacement of the working pump, and if the spool is killed, it can cause the pressure of one end of the servo piston without the change of the external load pressure, so that the discharge of the working pump is too large. Thereby, the engine is turned off. If there is a fault, replace the hydraulic oil and clean the PC valve to solve the problem.
