Possible causes of excavator weakness:
1. The air vent of the fuel tank cover is blocked, the diesel filter is blocked, the fuel tank switch is not fully opened, and there is air or moisture in the oil circuit, which makes the "low pressure oil circuit" blocked The air inlet and exhaust systems are not unblocked, the air filter is cleaned and maintained in time, it is partially blocked by impurities, and the carbon deposition of the exhaust pipe is serious.
2. The spring becomes weak or broken, or other springs that do not meet the requirements are replaced during maintenance; Some drivers directly bind the speed regulating spring with an iron wire, which loses the speed regulating function.
3. The wear of oil pump plunger pair, oil outlet valve, oil pump roller and camshaft oil supply cam reduces the oil supply of fuel injection pump and can not meet the needs of large load The oil quantity adjusting arm on the plunger pair of the oil pump is limited by the adjusting rod and cannot be turned to the maximum oil supply position.
4. The nozzle coupling parts of the fuel injector are seriously worn, the oil return and dripping are serious, the atomization is poor and the injection is biased, which makes the diesel combustion poor and affects the power of the diesel engine.
5. The fuel supply advance angle is too large or too small, the fuel supply time is too early or too late, the diesel engine produces deflagration or insufficient fuel combustion.
6. Some operators are inexperienced and mistakenly believe that the lower the temperature of the diesel engine, the better. They change the water frequently, or connect the cold water directly with the water tank during farmland irrigation, resulting in too low cooling water temperature, which may lead to the failure of the excavator
Failure inspection steps of excavator:
1. First, observe whether the diesel engine can reach the rated speed If the empty vehicle can reach the rated speed, but cannot reach it when loaded, it can be basically determined that the tension of the tension spring of the governor is normal; If the idle speed is very low, it is difficult to accelerate, it is difficult to increase the speed, it is easy to decelerate and the speed is unstable, it may be that the speed regulating spring is loose and the elasticity is weakened Check the tension of the speed regulating tension spring to increase the tension To identify the tension of the tension spring, take a new speed regulating tension spring, connect it in series with the old tension spring, and pull both ends with force If the pulling length of the old tension spring is longer than that of the new tension spring, it indicates that the tension of the old tension spring has been reduced and replacement should be considered.
2. When the diesel engine is started, if there is a crisp and serious knocking sound in the cylinder, it indicates that the oil supply time is too early When the cooling water temperature reaches boiling state, the knocking sound is eliminated, which indicates that the cylinder liner and piston are seriously worn. The previous knocking sound is not that the oil supply time is too early At this time, a small amount of engine oil can be injected into the cylinder liner. If the knocking sound weakens or disappears, it further indicates that the cylinder liner and piston are seriously worn (generally accompanied by difficulty in starting).
3. If there is no crisp knocking sound after the diesel engine is started, the explosion sound is dull, and the cooling water boils quickly, there is black smoke in the exhaust pipe, the exhaust temperature is high, and sparks appear in serious cases, it may be that the oil supply time is too late.
4 if the machine emits white smoke, it indicates that the diesel contains water or the temperature of the diesel engine is too low, and some diesel cannot be burned; Blue smoke (the empty car is serious, and the heavy car is reduced or eliminated), which may be due to serious wear of cylinder liner, piston ring and oil burning; Black smoke may be caused by poor atomization, too late oil supply time, dripping oil from the nozzle or poor compression, etc.
5. If the exhaust temperature is high, carbon deposits are discharged from the exhaust pipe and black smoke is emitted during operation, check whether the exhaust pipe muffler is blocked, and consider whether the air filter and valve clearance are adjusted correctly and whether the compression performance is good.
6. If it is found that the diesel engine has insufficient power, rough operation and high vibration, first check the fuel injection quality of the fuel injector and whether the fuel injection atomization is poor.
