Combustion engines are a combination of many different technologies. Thereby, the precision of each individual one is responsible for the performance of the engine. The actual injected amount of fuel for Common Rail engines is controlled by the lift height and the lift duration of the jet needles of the injector. Temperatures up to 150 °C, pressures up to 2000 bar and an electromagnetically sensitive environment make measurement evaluation difficult. The NLS miniature sensor of the eddyNCDT product group measures the needle movement at the tip of the injector where influences due to bending or compression of the needle do not even occur.