Generally, the failure of excavator shows that the engine speed drops more than 180 revolutions under normal operation, even if it is suffocating. First of all, it is necessary to clarify the starting direction and start the inspection from a simple aspect. Don't complicate the problem at the beginning. The engine power and the hydraulic pump power must not match. Usually, the elimination method is adopted, and the electromechanical and hydraulic 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: four keys 1234 from the top on the left, and four keys 5678 from the top on the right. Press and hold 8 while pressing and holding 3 and 4 for a few seconds, and then the display screen will appear (000000) enter the password (0e323a) first. 1 is to increase the number, 2 is to decrease, 3 is to move the flashing character right, 4 is to move left, and after entering, it will display (10---1), Adjust the speed to 12 to see if the maximum throttle is above 1850 when it is unloaded. If there is no speed or instability, check the speed sensor and circuit. If the speed is not enough to adjust the cable or the maximum throttle limit screw and throttle correction, and then adjust it to 16-2-of hanging wall pressure switch. When it acts, it will display 16-2-on. If there is no change, check the hanging wall pressure switch and circuit, measure the proportional solenoid valve (PS) pressure, and the normal is the maximum throttle no-load pressure 3. 0mpa working pressure value 1. About 6Mpa (related to adjustment), when holding the machine, PS pressure will rise with the decrease of rotating speed.
2. Check the hydraulic pump
High unloading pressure is also one of the reasons that lead to the choking machine. Check whether the power adjusting screw is adjusted too much. The plug oil seal in the adjusting screw and low throttling pressure are also the main reasons for the choking machine. The main reason for the low throttling pressure is that the matching gap between the servo piston of the control valve (elevator) and the pump housing is too large. The standard is no scratch, within 2 wires between the elevator and the pump housing, and within 5 wires between the servo piston and the pump housing.
3. Simple engine power check
Listen to the sound, no-load low idle, one by one cylinder is broken. Listen to whether the sound has changed. If it hasn't changed, it means that the fuel injector doesn't work (replace or clean). Quickly accelerate and listen to whether the sound of the engine comes fast, powerful and stable. If it's impossible, check the high-pressure pump, fuel injector, oil circuit, air inlet, valve and timing. Then look at the smoke color. When holding the engine, look at the black smoke degree of the exhaust pipe, which is divided into large, medium and small. It's most likely that the fuel injector and diesel are filtered, There is a problem with the air filtration and turbocharger, which may be due to insufficient air or oil supply in the diesel circuit. Check the oil pressure limiting screw, oil circuit and gasket.
