high-pressure fuel pump TSI (FSI) The following can be shown: How the inlet and outlet valves work. Up and down movement of the pump piston. How the pressure relief valve works. Fuel intake stroke, fuel recirculating, fuel pumping stroke. description ordernumber 500 see also: speed governor of a distributor-type injection pump single-acting fuel pump for DE (Diesel engines) visco blower two-spring injection-nozzle with needle-displacement sensor