20 classic fault cause analysis and maintenance methods for excavators?

What are the analysis solutions and maintenance precautions of the common failure of excavators?

1. Why is excavator difficulty in winter? Not only is it determined to be in its own technical condition, but also affected by the external temperature. It is more difficult to start at low temperature in winter, mainly caused by the following reasons:

⑴ The winter climate is cold, the ambient temperature is low, the oil viscosity increases, the friction resistance of each sports parts increases, the starting speed is reduced, and it is difficult to start.

随 The battery capacity decreases with the temperature, which further reduces the starting speed.

(3) Due to the decrease in starting speed and increased compressed air leakage, and the increased volume of the cylinder wall increases, the temperature and pressure of the compression end of the time and space are greatly reduced, which increases the delay period of diesel fire, and even in severe cases cannot be burned.

油 The viscosity of diesel at low temperature increases, which reduces the spraying speed. In addition, the spin speed, temperature and pressure of the air at the end of the compression are relatively low, making the diesel atomization quality sprayed into the cylinder poorly, and it is difficult to form a good good with the air quickly forming a good formation. The combustible gas and the fire and burning in time, or even the fire, resulting in the difficulty of starting.

2. What are the conditions for good starting performance of the excavator?

⑴ There must be enough starting speed. The starting speed is high, the gas leakage in the cylinder is small, the heat transmission time of the compressed air to the wall of the cylinder is short, and the heat loss is less, which increases the gas temperature and pressure at the end of the compression. Generally, the speed is required to be 1_0_0_r _/_ m_i_n_ or more.

要 The sealing of the cylinder is better. This can further reduce the amount of air leakage and ensure that the gas has sufficient burning temperature and pressure when the compression is at the end of the compression. The compression pressure of the cylinder must not be lower than the standard value of 8_0 _%_.

(3) It is required that the engine is properly lubricated compared to the operating machine parts.

The battery must have sufficient startup capacity, and the technical condition of the starting circuit is normal.

合 The amount of oil starting oil meets the regulations, the quality of the injection is good, and the early angle of the fuel injection must meet the requirements.

Use the fuel that meets the requirements

3. When the excavator starts, when the crankshaft cannot rotate the mechanical failure diagnosis and restoration of the engine, when the starting system is intact, press the starting switch. The starter has no sound and the crankshaft cannot rotate, which is a mechanical failure. The cause of the engine crankshaft cannot be rotated as described below.

① Poor the starter and the flywheel tooth. The gear and the starting gear will collide when starting the engine, causing tooth damage or single -sided wear of the teeth. If the teeth are severely damaged or wear severe, the starter gears and gear tooth teeth are difficult to mesh.

② Sticky tank. When the engine temperature is too high, the parking is stopped, and the heat is difficult to spread. The piston ring at high temperature is adhesive to the cylinder, and it cannot start after cooling.

③ The crankshaft is hugged. The sliding bearing friction caused by the lubrication system fault or the lack of oil, which eventually hugged the crankshaft and could not start.

④ The fuel jet pump plunger died.

4. The excavator can be rotated when starting, but the diagnosis of no starting (non -smoke in the exhaust pipe). When starting the engine, the exhaust pipe is exhausted without smoke, and there is no sound of explosion. Generally, it is a problem of oil circuit. The detailed analysis is as follows:


① No oil in the fuel tank.

、 Fuel filter and oil and water separator are blocked.

③ The low -pressure oil road does not supply fuel.

④ no oil pump pump oil.

⑤ There is air in the oil road.

⑥ The phase of the gas distribution is accurate. The opening of the valve is not coordinated with the piston in the cylinder. If the piston is used in the cylinder for a compressed itinerary, the entrance and exhaust doors are opened, and the fresh air is kicked out of the cylinder, so that there is no burning gas in the cylinder and cannot start.

⑦ The solenoid valve of the type of fuel injection pump is broken and is closed. Diesel cannot enter the high -pressure cavity.

5. The excavator is difficult or unable to start, and the exhaust pipe is diagnosed with a large amount of white smoke. When the engine starts, the reasons for the exhaust pipe to discharge a large amount of white smoke are analyzed as follows:

① There is water in diesel, and the water evaporates into water vapor in the cylinder, and is discharged from the exhaust pipe.

② The cylinder head bolts are loose or the cylinder pads are broken, so that cooling water enters the cylinder.

③ Somewhere in the cylinder or cylinder head is trachoma or cracks, and the water enters the cylinder to evaporate and discharge.

6. The excavator is difficult or unable to start, and the exhaust pipe is diagnosed with a large amount of gray smoke. The engine is difficult to start, and a large amount of gray smoke is discharged from the exhaust pipe as diesel steam.

① The engine temperature is too low, and the diesel is not easy to evaporate.

② Poor atomization

③ The oil supply time is too late.


④ Excessive fuel supply, mixed gas is too thin.

⑤ Excessive amount of air leakage in the cylinder, and the compression cannot reach the fire temperature.

7. The excavator is difficult to start or cannot start, and the exhaust pipe is diagnosed with a large number of black smoke. The engine is difficult to start, and the exhaust pipe is largely discharged by black smoke, which is the result of incomplete diesel burning.

① Diesel quality is poor

② The air intake is not smooth, and the air filter is blocked.

③ The fuel injection is prematurely adjusted prematurely.

④ The scoop valve is poorly sealed and there is a leakage of oil.

⑤ The fuel injection pressure is too low.

⑥ The fuel injection pump has too much fuel supply, and the combustion worsen.

⑦The cylinder pressure is low and poor atomization.

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8. Diagnosis of the engine with difficulty starting the engine is good at starting, but after a period of time, the temperature rises after the temperature rises, and it is difficult to start with the strict wear of the fuel injection pump plunger and the sub -injection valve. When the hot car starts, due to the high temperature of the fuel injection pump and the fuel filter, the fuel viscosity decreases, and the starting speed is low. Most diesel leaks from the gap of wear, resulting in insufficient starting oil.

9. The excavator is normal at low speed and has a short -term high speed. The engine has a good idle speed, the speed of the throttle can rise rapidly, but the continuous throttle speed is not easy to rise, the driving is weak, or the use of medium speed or above cannot be driving. This is caused by insufficient low pressure oil supply.

① Diesel filter or oil and water separator is blocked.

② The low -pressure oil road is not smooth.

③ Insufficient oil supply or oil -in -in -in -in -in -in -be -in -in -in -be -in -in -law filter is blocked.

④ The fuel tank covers the air valve to fail. The above situation can cause insufficient low fuel fuel pressure in the fuel injection pump, and can only maintain the fuel supply required for small loads. When large and medium loads need to be used more fuel supply, they cannot be satisfied, so that driving is weak.

10. The excavator is normal but has no high speed, no high speed, and too little smoke diagnosis.

The engine is good at low speed, but the speed of speed does not increase when the acceleration is accelerated. The driving is weak. This is caused by insufficient circulating oil supply.

① Improper adjustment of the fuel jet pump to reduce the amount of oil supply.

② The speed of the speed regulator spring is reduced due to fatigue. When the accelerator is stepped to the end, the oil volume adjustment lever cannot move forward, resulting in a reduction in the fuel supply of the fuel injection pump, and the engine cannot reach the rated speed

③ The fuel injection pump plunger and sleeve, the needlejet needle valve and the needle valve body severely wear, which increases the leakage of diesel during pump oil, and the oil supply supply is relatively reduced.

④ Improper adjustment of the tidal rod, or the throttle pedal is sold out, so that the throttle pedal cannot be in place, resulting in too much full load fuel supply.

11. Insufficient mobility, the diagnosis and analysis of the failure of gray and white cigarettes are as follows:

The engine is insufficient, and the exhaust pipe is ash and white smoke, which is generally caused by too late in the fuel injection time. At this time, it is not only poorly operated at high speed, is not sensitive to accelerate, but also is easy to be too high.

① The fuel injection early corner is too small.

③ The engine temperature is too low.

④ Water in the cylinder.

⑤ There is water in diesel

12. Analysis of the cause of the failure of the mobility, the cause of the heavy black smoke:

There are two types of engine power, uneven speed, and two types of exhaust tubes: one is to continuously discharge black smoke; the other is to discharge the smoke intermittently, and the engine shakes. The engine power is insufficient and continuously discharged to smoke. It is the most of the engine or all the cylinders of the engine. The amount of fuel and the air mixed proportional disorders, severe hypoxia when burning The exhaust gas was formed together. If the exhaust pipe is discharged from the smoke, it is accompanied by a “sudden” sound, indicating that the burning of individual cylinders is incomplete. The reason for induction is as follows

① Improper debugging of the fuel injection pump, too much fuel supply, incomplete combustion.

② Poor jet quality of most injectors.

③ The oil supply is not positive.

④ The high degree of opening and delay in the opening of the intake valve leads to insufficient air intake.

⑤ The air filter element is too dirty or the air filter is installed error to make the air not smooth.

⑥ The pressure of supercharger has decreased.

⑦ The quality of fuel is too poor.

13. Insufficient mobility, diagnosis and treatment of blue smoke.

When the engine is low at low temperature or small load, it turns into dark gray smoke after the temperature rises, and is insufficient.

① Poor air intake, causing oil to be inhaled into the cylinder burning.

② _Thorus oil in the oil bottom shell, the oil exceeds the highest limit.

③ The valve catheter enters the port oil.

④ The cylinder is severely channeled.

⑤ The rotor axis of the supercharger is severely worn, and the oil block is damaged, resulting in the not reaches the rated speed of the supercharger, leakage oil

14. Why is a supercharger the most prone to failure on the engine?

Because the rated work speed of the supercharger is more than 130,000 per minute, and at the exit of the exhaust manifold, the temperature is extremely high (above 800 ° C), the inlet and exhaust pressure is also large, that is, high temperature, high pressure, and high speed speed speed Therefore, the requirements for lubrication and cooling and sealing of the supercharger are relatively high. In order to ensure the service life of the supercharger, the design must ensure the lubrication and cooling of the booster’s floating bearing. At the same time, the requirements are required to do:

① After the engine starts, it should run for 3-5 minutes. Do not add the load immediately to ensure the good lubrication of the supercharger. The main reason is that the supercharger is located at the top of the engine. If the supercharger starts at high speed after the engine starts, it will cause the oil pressure to fail to increase the oil supply in time, cause the supercharger to damage the oil, and even burn it even burning Bad the entire supercharger.

② The idling time should not be too long, generally not more than 10 minutes, and the long time is too long to cause oil to leak oil.

③ _ Do not turn off the engine immediately before parking. You should idle speed for 3-5 minutes to reduce the temperature of the supercharger and the temperature of the exhaust system to prevent failure of the heating-oil coke-bearing damage. Regular incorrect use can damage the supercharger.

④ The engine that has not been used for a long time (usually more than 7 days), or the engine with a new supercharger should add the oil inlet of the oil inlet of the supercharger before use, otherwise it will reduce life due to poor lubrication or damage the supercharger to the supercharger. Essence

⑤ Regularly check whether there is a loose gas leakage in each connection area/_ oil leakage, and whether the oil return pipe is unobstructed, if there is any timely exclusion.

⑥ Ensure that the air filter is cleaned and replace it regularly as required.

⑦ Regularly replace the engine oil/_ oil filter.

⑧ Regularly check the radial axial gap of the axis of the booster. The axial gap should not be greater than 0.15 mm. The radial gap is: the gap between the impeller and the shell is not less than 0.10 mm.

15. Why do the excavator some of the engine on the engine is damaged?

① The lubricating oil is not clean.

② There are impurities in the oil duct.

③ There are foreign objects in the exhaust pipeline

16. Analysis and fault treatment of the cause of no idle speed: no idling at the engine, generally manifested as the throttle at the idle position, and when the throttle is slightly increased, the speed rises quickly, and it cannot operate at low speeds at low speeds.

① The speed regulator idle spring is too soft or broken.

② The speed regulator sensor component is too large.

③ The fuel jet pump plunger is severely worn.

④ The temperature is too low.

⑤ Excessive pressure of cylinder

17. Analysis and fault treatment of the reasons for excessive idle speed of the excavator: The engine speed is too high. When it is lifted up the throttle, the engine speed is still higher than the specified value of the idling speed.

① Improper adjustment of the throttle manipulator.

② The throttle return spring is too soft.

③ Limit at idle speed or adjust screw disorders.

④ The idle spring is too strong or the pre -tightening adjustment is too large

18. Analysis and failure diagnosis of the cause of unstable idle speed of excavator: The expression of the unstable speed of the engine is when the idling is running slowly, or there is vibration, which makes the machine turn off when slowly slowing or shifting. The analysis of the detailed reasons is as follows:

① There is air in the oil road.

② The low pressure oil road supply is not smooth.

③ Improper adjustment of idle stabilization device.

④ Poor lid.

⑤ Unewal oil supply of fuel injection pumps.

⑥ Excessive wear of the sales axis and fork head of the connected rod of the speed regulator

19. Analysis of the cause of sudden flameout during the operation of the excavator? During the operation, the engine suddenly stopped refers to the phenomenon that the non -driver’s operating factors did not release the operating factors without the operating factors of the driver when the engine was working. This phenomenon is generally caused by mechanical failure, as follows:

① The fuel injection pump drove the tooth break and drive the gear failure.

② Break the fuel injection pump axis.

③ The internal motion parts of the engine is stuck.

④ The fuel injection pump manipulates the lever and connected to the sales and falls off

20. Analysis of slow flameout during the operation of the excavator: Slowly turning off the engine when the throttle is not loosened, generally caused by the non -timely or interruption of oil supply. Its manifestations are gradually weak during the engine operation, and finally automatically turn off.

① All diesel in the fuel tank.

② The fuel tank cover ventilation valve is blocked.

③ The fuel filter or oil and water separator is blocked.

④ Fracture or infiltration of the fuel pipeline.

⑤ The oil pump does not work.

⑥ Water in the fuel tank

⑤ There is air in the oil road.

② Poor atomization

If there are any problems with the excavator high temperature pull cylinder and excavator maintenance, consultation, information, technical support, experience sharing, communication, after -sales service, technical support can be


Communicate, communicate, thank you.