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8 reasons for the engine speed drop of the excavator, 6 solutions are here!

As the name suggests, engine speed drop means the failure of the engine speed drop during the operation of the excavator. There are two manifestations of speed drop, one is a slight speed drop within 200 revolutions, and the other is a serious speed drop above 300 revolutions, which is likely to cause the excavator to suddenly shut down. There are 8 main reasons for the engine speed drop of the excavator.

1. The diesel oil circuit of the excavator is faulty. Generally speaking, when the diesel oil circuit is blocked, it may cause the speed drop phenomenon.

2. The hydraulic system of the excavator has a fault, so that the hydraulic pump cannot change the displacement normally, causing the system pressure to be too high, and the speed drop may also cause a machine failure.

3. The output power of the excavator engine itself is insufficient, the output power is lower than the rated power, and the speed is too low. There is also a problem with the main pump.

4. The engine uses fuel of poor quality or the water content of the fuel is too high, which will lead to insufficient engine power and speed drop.

5. When the air intake system leaks or is blocked, the engine will be short of air supply, resulting in incomplete combustion of fuel, and there will be speed drop and black smoke failure.

6. Due to the large gap of the solenoid valve, the fuel supply is insufficient, which causes the engine to drop.

7. The joint of the fuel supply circuit of the fuel system is loose or the pipeline is broken, causing fuel leakage or foreign matter blockage, resulting in insufficient fuel supply. In addition to speed drop, it may also cause flameout.

8. There are many reasons for speed drop, such as incorrect valve clearance, wrong injection timing, damaged turbocharger, faulty brakes, etc.

Having said so many reasons for the speed drop of the excavator engine, what should we do when the speed drop occurs?
The solutions are all here!

1. First, check whether the diesel used in the excavator is deteriorated, whether there are impurities in the oil, and whether the oil circuit is blocked.

2. Check the valve clearance of the excavator engine and the speed of the engine.

3. Check the intake pipeline, clean the air pre-filter and air filter element, and start the engine again.

4. Check whether the speed drop of the excavator occurs when the engine is under load?

5. Carefully check the engine to see if the engine failure causes the speed drop of the excavator engine.

6. In addition, the electronic control, hydraulic system, fuel system, etc. need to be checked.

Possible low hydraulic oil, clogged filter, high ambient temperature, or excessive load.

Solution: Refill hydraulic oil, clean or replace filter, ensure good ventilation, reduce system load.

Possible internal component wear, clogged filter, oil contamination, or insufficient system pressure.

Solution: Replace worn components, clean or replace filter, replace hydraulic oil, check and adjust system pressure.

1. 1. Insufficient air intake: Check whether the intake valve clearance is within a reasonable range. Unequal valve clearance will cause insufficient intake pressure and volume; whether the air filter is clogged. The supercharger is damaged, resulting in insufficient intake pressure;

2. The diesel quality is poor, and the diesel pump and fuel injector are worn;

3. Injector wear: Excessive fuel injection leads to incomplete combustion. Service personnel are required to perform an engine cylinder disconnection experiment to check whether it is caused by wear of the fuel injector.

When the engine replaces new piston rings, pistons or cylinder liners, due to the initial poor running-in, it is easy for the engine oil to enter the combustion chamber and burn, producing blue smoke. This phenomenon can generally be gradually eliminated after running for 8-10 hours.

(1) The oil level in the oil pan is too high.

(2) The engine oil in the air filter leaks into the combustion chamber from the intake pipe and burns.

(3) The piston ring is bonded to the piston ring groove by carbon deposits, causing the engine oil to leak into the cylinder and burn.

(4) The piston ring is excessively worn, or when several piston rings are installed, the opening gap has been matched.

(5) The matching clearance between the piston and the cylinder liner is too large.

(6) The piston ring is not elastic enough.