Generally, the failure of an excavator is manifested by the engine turning more than 180 rpm under normal work, even if it is a suffocating machine. First of all, it is necessary to clarify the starting direction and start the inspection from a simple aspect. Do n’t complicate the problem at the beginning. The holding machine must be the power of the hydraulic pump of the engine power. The exclusion method is usually used, and the electromechanical fluids are eliminated one by one.
Inspection and analysis:
1. Check the circuit
First adjust the working mode to boom priority, set the user mode to U3, and then enter the monitor as follows: the left side counts four keys from the top 1234, the right side counts from the top 5678 four keys, press 8 while pressing After holding 3 and 4 for a few seconds, (000000) appears on the display screen. Enter the password (0E323A). 1 is to increase the number, 2 is to decrease, 3 is to move the flashing character to the right, 4 is to move to the left, and it will display (10 --- 1) after entering. Adjust to 12 to see if the maximum speed throttle is above 1850 when there is no load, there is no speed or instability Check the speed sensor and circuit, the speed is not enough to adjust the cable or the maximum throttle limit screw and throttle correction, and then adjust to 16-2-OF The disc pressure switch will display 16-2-ON when it is in action. Check the disc pressure switch and the circuit without change. Measure the pressure of the proportional solenoid valve (PS). The normal pressure is the maximum throttle no-load pressure. 3. 0MPA working pressure value is 1.6MPa Left and right (related to adjustment), the PS pressure will increase as the speed decreases when holding the machine.
2. Check the hydraulic pump
The high unloading pressure is also one of the reasons for the gap to hold the machine. Check whether the power adjustment screw is adjusted too much. The adjustment screw has a plug oil seal. Low throttle pressure is also the main reason for holding the machine, resulting in low throttle pressure. The main reason is that the control valve (lifter) servo piston and pump housing have a too large clearance. The standard is no scratches. The lifter and pump housing are within 2 wires, and the servo piston and pump housing are within 5 wires.
3. Simple engine power check
Listen to the sound, no-load low idle speed, one after another cylinder, listen to whether there is any change in the sound, no change indicates that the injector is not working (replace or clean), and quickly accelerate to listen to the sound of the engine. Is the sound coming quickly and powerfully? It is not possible to check the high-pressure pump, fuel injector, oil circuit, intake air, valve, timing, and then look at the smoke, and the black smoke level of the exhaust pipe when holding the machine is divided into large, medium, small, probably There is a problem with the fuel injector, diesel filter, air filter, and turbocharger. It is likely that the diesel circuit has insufficient air intake or fuel supply. Check the oil pressure limit wire and the oil circuit and gasket.
