When the excavator is in use, the diesel pump may fail and give an alarm. If the excavator is equipped with ECU, the corresponding fault code will appear. Understanding the fault code can more effectively check and repair the excavator. This article will analyze several common codes of diesel pump failure for reference only.
Under the control of ECU, the diesel pump generates high-pressure fuel and sends it to the common rail to generate pressure. The output fuel is controlled by the diesel oil volume regulating SCV valve on the diesel pump, and the SCV valve is electronically controlled by ECU.
The diesel oil is sent to the three plungers through the filter element, low-pressure pump and SCV valve. The oil supply pump is driven by the camshaft. The inhaled fuel outputs the necessary amount of oil from the output port to the SCV valve with the rotation of the roller. SCV is an inverse proportional valve. If the current value increases, the diesel flow decreases, and the rest returns to the oil suction port through the regulating valve.
The following is the common code analysis caused by diesel pump component failure:
1）P0183、P0187、P0188
Check the fuel temperature sensor. Firstly, visually check whether the harness is loose. Secondly, check the resistance value on the ECU side of the harness, 2.45k Ω at 20 ℃ and 1.15k Ω at 40 ℃. If it is normal, remove the sensor connector and measure the resistance value of the two electrodes at the sensor end. 2.45k Ω at 20 ℃ and 1.15k Ω at 40 ℃ are used to eliminate whether it is caused by poor harness contact. If the sensor fails, it needs to be replaced.
2）P0628、P0629、P2635
The above three codes are the alarm after the wire of SCV valve is unplugged, which belongs to the normal disconnection alarm. It is necessary to check the rear connecting harness. If the harness is normal, you can check whether the valve core of SCV valve works normally when it is powered on. The SCV valve is stuck, most of which is caused by unclean fuel. It is recommended to clean the oil circuit and replace the diesel filter element. If the fault cannot be eliminated, contact the service personnel to check whether the resistance value between terminals on the solenoid valve side is within the normal range.
