The parts of the fuel injection system are intended for fuel delivery with the subsequent injection into the combustion chamber. The fuel is pumped under pressure through a network of pipes and tubes through various bifurcations, angles, etc. During pumping the fluid acquires a directed rotation due to the construction of parts. Then through nozzles, injectors and spray heads with lots of small holes, the fuel, in the form of a gas cloud, gets into the engine combustion chamber. All parts of this system have special technical manufacturing requirements. Special difficult-to-process materials are used: austenitic stainless steel, heat resistant steel, titanium alloys. When machining, a special attention is paid to deburring because small remaining burrs could close the small holes through which fuel is pumped. Also a good roughness with an accuracy up to a few microns is necessary. These parts are subjected to 100% technical inspection in the Technical Control Department. Sometimes special quality control methods of the surface layer cracks like colour penetration and magnetic powder inspection are used.