FUEL INJECTOR FOR A COMBUSTION ENGINE

A fuel injector has a head portion (12, fig.1) providing connections (15, fig.1) from and to an ECU (16, fig.1) to selectively energize an actuator (18, fig.1) controlling injection pulses, fuel supply and return connections, an injection nozzle (26, fig.1) having at least one opening at an end of a valve guide, and a biased to close valve member (32, fig.1) in a chamber within the valve guide. A circuit is provided for detecting by an electrical change whether the nozzle is open or closed. The circuit includes a conductor 130 extending between the head of the fuel injector, either in an outer region of the body of the injector or through an isolation member 102 for the actuator, to a position generally at a head end of the actuator, a contact member 118 at the head end of the actuator maintained in electrical contact with the conductor and a resilient electrical link 126, preferably comprising a spring, between the contact member and the valve member or valve guide.