The influence of diesel engine power is mainly determined by the working conditions of the compression system and the fuel supply system. Therefore, the following factors affect the power of the engine: 1. The compression system is in poor condition. 1.1 The compression ratio becomes smaller: The valve subsidence and the bearing neck wear cause excessive clearance. The injector and the cylinder head gasket are not installed according to regulations. The increase of the combustion chamber space will cause the compression ratio to become smaller, reduce the pressure at the end of compression, and reduce the power. 1.2 Cylinder pressure reduction: Wear of piston rings and cylinder liners, lax sealing of valves and seats, etc. 2: The fuel system is not working properly. 2.1 The low pressure oil line is blocked and the fuel cannot enter the fuel injection pump normally. 2.2 The air is sucked into the oil circuit so that the fuel pump cannot be supplied with oil. 2.3 Plunger wear, supply pressure is too low. 2.4 The air filter is blocked and the intake air is insufficient. 2.5 The piston of the fuel pump is stuck or the spring is broken. 2.6 Nozzle injection pressure is too low or the needle stuck. 3: Gas phase and fuel injection time changes? 3.1 timing gear room, the various gears are not installed correctly. 3.2 The camshaft cam wears badly. 3.3 Valve gap adjustment is incorrect or changes during use. 3.4. The location of the fuel pump is incorrect. 3.5 Injection pump camshaft wear. 3.6 Nozzle injection pressure adjustment is wrong. 4: other factors? 4.1 injector nozzle needle overshoot, increasing the injector fuel injection continuation angle, which extends the post-combustion period, resulting in engine power shortage, abnormal temperature. 4.2 The clogging of fuel injectors leads to a gradual increase in the amount of dirty fuel on the injectors, and there is a certain pressure, so that the needle valve movement is hindered and the performance of the injectors deteriorates. 4.3 The combustion chamber has serious carbon deposition, which affects the mixing quality of fuel and air, and the body temperature is abnormal.