How to check the speed drop of the excavator

First, test the output power of the engine itself.

Following parts you may need to check

• air valves https://www.fridayparts.com/engine-spare-parts/intake-exhaust-valve
• fuel injectors https://www.fridayparts.com/engine-spare-parts/injectors-nozzle
• turbocharger https://www.fridayparts.com/engine-spare-parts/turbocharger
• hydraulic pump https://www.fridayparts.com/hydraulic-parts/hydraulic-pump-parts

If the output power of the engine is lower than the rated power, the causes of the failure are as follows:

• Poor fuel quality;
• Low fuel pressure;
• Incorrect valve clearance;
• A particular cylinder of the engine not working;
• Wrong fuel injection timing and the fuel setting value is incorrect;
• The air intake system is leaking;
• The brake and its control lever are faulty;
• And the turbocharger is carbonized.

If the output power of the engine is normal, it is necessary to check whether the flow rate of the hydraulic pump matches the output power of the engine.

The speed of the hydraulic excavator is inversely proportional to load during operation. The product of flow rate and pump output pressure is invariant, and the output power of the pump is constant or approximately constant. If the pump control system fails, the optimal load matching state of the engine, pump, and valve cannot work in different working conditions, and the excavator will not work usually.

Such failures should start with the electrical system, check the hydraulic system, and finally check the mechanical transmission system.