Method for controlling a fuel injector of an internal combustion engine

Process for controlling an injection valve of an internal combustion engine, especially a piezo injector, during the start-up phase of the engine comprises rotating the crankshaft of the engine using a starting motor, especially an electric starting motor, loading the actuator of the injection valve with a control signal that changes on reaching the maximum needle stroke of the actuator, and evaluating this change in control signal. Preferred Features: The fuel injection quantity per piston stroke is at least 20 mg.