Pressure intensifier having a guiding insert for a fuel injector

The fuel injector has a pressure intensifier with a piston which separates a working chamber (11) from a differential pressure chamber (16) and which pressurizes a compression chamber (19) from which runs a HP line (21) to an injection valve component housed in a nozzle component. The piston of the pressure intensifier is housed in a guide component (30) in a guide element (31) which is housed in the fuel injector with a radial clearance (36).