Kyotechs Hitachi Hydraulic Pump Spare Parts List

Abnormal exhaust smoke can indicate various engine issues:

1. Black smoke: 

Check for clogged air filters, over-fueling, or issues with the fuel injectors. Inspect the turbocharger (if equipped) for damage.

2. Blue smoke: 

Indicates oil burning. Check for worn piston rings, valve seals, or a damaged turbocharger.

3. White smoke: 

Can be caused by coolant entering the combustion chamber. Inspect the cylinder head gasket, cylinder head, and cooling system for leaks. Additionally, ensure the fuel injectors are operating correctly and not causing unburned fuel to emit as white smoke.

Digging powerlessness can be divided into two situations: one is digging powerlessness, the engine does not hold back, and the load feels very light; the second is digging powerlessness, when the boom or dipper stick is extended to the bottom, the engine is seriously held back or even stalled.

①, digging powerlessness but the engine does not hold back. The magnitude of the digging force is determined by the output pressure of the main pump, and whether the engine holds back depends on the relationship between the oil pump absorption torque and the engine output torque. The engine does not hold back, indicating that the oil pump absorption torque is small and the engine load is light. If the working speed of the excavator is not obviously abnormal, the maximum output pressure of the main pump, that is, the system overflow pressure, should be checked in particular. If the overflow pressure measurement value is lower than the specified value, it indicates that the overload overflow valve setting value of the hydraulic circuit of the mechanism is incorrect, resulting in premature overflow of the mechanism and powerlessness. The machine can be adjusted by turning the adjustment screw.

②, digging powerlessness, engine holding back. The engine holding back indicates that the absorption torque of the oil pump is greater than the engine output torque, causing the engine to overload. This fault should first check whether the engine speed sensing system is normal, and the inspection method is similar to the engine inspection method described above. After the above detailed inspection and troubleshooting, the engine speed sensing system will resume normal function, the engine stalling phenomenon will disappear, and the digging force will return to normal.

This is because the valve plate was over-ground during maintenance and the grinding amount was too much, so the pressure between the valve plate and the cylinder plane is insufficient. At low throttle, the oil pressure is small, and it is not easy to leak between planes; at high throttle, the oil pressure increases, and overflow occurs between planes, causing the track to be unable to move at high throttle. The remedy is to add a gasket to the spring. If it is a butterfly spring, you can add an extra butterfly spring.

To diagnose a faulty fuel injector, listen for any unusual engine noises or misfires. Perform a balance test to identify which injector is causing the problem. Use a diagnostic tool to check for fault codes related to the fuel system. If necessary, remove and inspect the injector for signs of clogging or damage, and replace it if needed.