What are the reasons for the general speed loss of Komatsu 210 7 excavator?

Merritt Excavator Repair Factory Master Li analyzed.

Excavator engine speed failure cause:

1 Under normal circumstances, if the excavator drops speed within 200 and does not affect the work of the excavator, you can check whether the inlet pressure sensor of the excavator is damaged? (It may be due to the poor working environment conditions of the excavator and the lack of replacement of the air cleaner for a long time, resulting in damage to the inlet pressure sensor.) )

2 More than 200 is likely to cause the phenomenon of suffocating the car and stalling, and the reasons for the failure are as follows:

Problems with the oil circuit or leakage in the air intake system.

The engine air intake is insufficient or leaking, the final cooler is not cooled enough, and the intake air temperature is high.

Diesel problems or excessive wear and tear on the diesel pump.

Problems with the components of the engine itself. It is recommended to adjust the valves, check the fan speed, water temperature radiator.

If the engine load drops speed or even holds the car and turns off, it is likely to be caused by insufficient oil supply, it is recommended to check the oil circuit and circuit, check the fuel filter and other filtration devices, if the filter is blocked, the oil supply will not be smooth, and the excavator engine will turn off the speed. In addition, it is normal for the engine to suddenly increase the load and the speed decreases.

If the excavator operates at high altitude and the engine turns off the speed, the main reason is that due to the change of engine load or insufficient air intake, when the hydraulic system of the excavator fails, the pump displacement cannot be changed, which is easy to lead to the phenomenon of falling off speed and holding the car.

There are two main reasons why the engine speed of an EFI engine is slowed down: a decrease in engine performance or a problem with the main pump. At this time, you need to check the engine and main pump, remove the hydraulic filter element, and see if there is any copper powder?

If there is copper powder, the main pump is worn; Or enter the monitoring panel to check the engine speed, the idle speed of the small throttle is 1000 rpm, the idle speed of the large throttle is 1300 rpm, and the maximum throttle is 1900 rpm, and the solenoid valve on the main pump is removed and cleaned, and the fault can be eliminated.

Generally speaking, it is the load that is too heavy to carry it.

Summary. It is recommended to check the low-pressure oil circuit, high-pressure oil circuit, intake and exhaust system, etc., as well as the cylinder compression force.

Hello, I have seen your question and am sorting out the answer, please wait for a while It is recommended to check the low-pressure oil circuit, high-pressure oil circuit, intake and exhaust system, etc., as well as the cylinder compression force.

It could be that there is a problem with the circuit, not the engine.

You're going to have a multi-faceted check!

If it's a circuit problem, where is it?

The engine was inspected by a mechanic and it was no problem. If there will be problems with hydraulics and circuits, please inform <>

Hello! It still needs to be inspected on site! You don't think you can even check the problem on the spot! I can't judge it on the Internet in a few words!

There is also a problem, the excavator vibrates a lot, and the whole action will slow down, just like idling.

Check the cylinder pressure and high-pressure oil circuit! Sometimes it's a small problem! Leaky gaskets can also cause the problems you say!

Have you checked the computer control board?

Can you give us a general direction?

If the speed is slowed, it is recommended to check the computer controller!

Excavator engine speed loss refers to the phenomenon that the engine speed decreases during the operation of the excavator.

First, the excavator engine speed reduction performance:

1. The excavator engine slows down slightly (within 200 rpm);

2. The excavator engine is seriously slowed down (more than 300 rpm, which may seriously lead to the failure of the excavator).

Second, the reason for the speed loss of the excavator?

1. Some cars use the solenoid valve (fuel cut-off) to control the oil circuit and cut off the oil, so as to achieve the purpose of stalling.

I have encountered a similar problem, the gap of the solenoid valve is too large, just like the effect of flame-out wire drawing, with load resulting in insufficient oil supply, so the speed is reduced, and the speed loss leads to insufficient oil supply to the diesel pump, which is a vicious circle, which eventually leads to flameout.

2. The influence of temperature is relatively small, after all, there is a cooling device, the influence of the environment is mainly air pressure, for high altitude areas, the air is thin, the oxygen content is low, the engine combustion is insufficient, which affects the engine performance, but the air supercharger also reduces the impact of high altitude.

The main reason for the engine speed loss is the change of load, when the hydraulic system fails, the displacement cannot be changed, which can easily lead to speed loss or car holding.

3. There are two main reasons for the speed loss, the engine performance is reduced, the main pump is problematic, check the engine and the main pump.

You can first take out the hydraulic filter element and take a look, if you see a lot of copper powder on the filter element, it means that there is a problem with the main pump and the main pump needs to be overhauled.

You can also enter the monitoring panel to check the engine speed, the minimum throttle idle speed is more than 1000 rpm, the maximum throttle idle speed is more than 1300 rpm, and the maximum throttle is more than 1900 rpm.

If there is no copper powder and the engine speed is normal, the two solenoid valves on the main pump can be removed and cleaned, and the problem can be basically eliminated.

4. If the output power of the engine is much lower than the rated power, then the judgment at the construction site should start with the simplest method.

First of all, see whether the fuel filter element is blocked, whether there is an air leak in the fuel circuit, whether the plunger in the fuel pump, the fuel injection head, and the oil outlet valve are seriously worn, whether the air intake of the air filter element is smooth, whether the engine with turbocharger is damaged, whether the engine is fast and high temperature, the oil viscosity decreases, resulting in the cylinder wall sealing is not tight, the compression ratio decreases, whether the cylinder liner assembly is worn out and causes serious gas cross-traffic in the cylinder, and the engine valve is not tightly closed, etc., these are all factors that seriously affect the engine power.

If the insufficient output power of the engine itself is ruled out, it is necessary to consider the matching of the flow rate of the hydraulic pump and the output power of the engine.

Hello, it is an honor to be able to answer this question for you, according to your description, the excavator is slow and powerless to deal with: 1 After arriving at the scene, the test machine found that the machine was very slow and slow. 2 preliminary suspicion may be that the pilot pressure is not enough to cause the excavator to move slowly and weakly, so the car on the table to measure the pilot pressure of the excavator, found that the pilot pressure is only 20, and the standard pilot pressure value is 32, this pressure value is far from the standard deviation.

3. Because the pilot pressure value is far from the standard, it is suspected that the self-reducing valve is stuck, and the valve core is found to be stuck after disassembly, and it is ground and installed after taking it out, and the pilot pressure value is measured and found that the pilot pressure is 40Now the pilot is normal, and I find that the action is a little faster than the original, but it is still slow. 4. Carefully test the machine, and find that when suffocating, the excavator does any action The engine seems to have no load, just like the flow is very small.

5So, check the hydraulic oil of Komatsu PC200-6 excavator, and find that the hydraulic oil is dark yellow, and it is suspected that the load relief valve is stuck. 6. Remove the 2 unloading valves and install them on the test machine after cleaning, everything is normal, Komatsu PC200-6 hydraulic excavator is slow and weak for troubleshooting.

Komatsu 56 is slow to move how to deal with it.

Hello, it's an honor to answer for you.

1. Failure to replace the hydraulic oil in time according to the actual situation or maintenance time leads to the deterioration of the hydraulic oil or the lack of hydraulic oil and the blockage of the hydraulic oil filter element, resulting in insufficient oil absorption of the hydraulic pump and the reduction of the oil supply transmitted by the hydraulic pump to the distribution valve, which is one of the reasons for the slow and weak action of the excavator. 2. The pilot pressure is insufficient. When the pilot pump is damaged or the pilot filter element is blocked, it is the direct cause of the pilot pressure is too low, resulting in the operation handle or foot valve stem can not be fully opened, which causes all the movements of the excavator to be slow and weak.

3. The main relief valve is worn (also known as the main and auxiliary guns). The main relief valve is to control the main overflow pressure of the whole vehicle, once worn or carded, all the actions of the whole vehicle will be affected. If it is often stuck in a certain position, it will cause the whole vehicle to be slow and weak, and in serious cases, it will be accompanied by a harsh overflow sound, resulting in the excavator can not work normally.

The whole vehicle of the excavator is slow to move, which means that no matter what the excavator does, the speed of the whole vehicle is very slow and weak. Common causes are:

The engine speed is not too low enough or the engine power is not enough.

The output flow of the hydraulic pump of the excavator is small.

Excavator CPU, high and low voltage sensors, solenoid valves and circuits are abnormal.

The hydraulic components of the excavator are abnormal, the oil circuit is abnormal or the flow is lost.

The pressure value of the excavator pump is small, which is lower than the normal value, resulting in the slow action of the excavator.

Excavator pump components wear out, a factor that often occurs on used or long-term excavators. The inspection method is to drain the oil to see if there are iron filings or other impurities in the oil, if there are iron filings, it means that the pump assembly is worn.

Insufficient pilot pressure or failure of the PC-EPC solenoid valve.

Electrical problems. (This problem is common with Kobelco excavators, and Kobelco excavators have more circuit problems).

Cause of failure] Komatsu PC220-8 excavator boom speed is slow, there is vibration animal slow.

1 Boom regeneration valve failure.

2 Check valve bite which to kill the cover source.

3. Internal leakage of the control valve.

Fault check] 1 After starting, operate and get on the car, support the boom and drop the boom, and confirm the fault phenomenon.

2. Check whether the check valve has bite, if there is bite, there will also be boom operation vibration or slow phenomenon, check normal.

3. Check whether there is internal leakage of the control valve (the hydraulic leakage of the excavator is mainly generated inside the boom slide valve and the oil cylinder, which is not easy to check), and the problem is found to be here.

4. Reinstall the control valve after overhauling, start the test machine, everything is normal, the boom speed is slow, the vibration phenomenon disappears, and the fault is solved.