An engine controller system employs angular position sensors which are operable to very accurately determine the position of rotating engine members. Information about the angular position of the engine members is used to alter operation of the engine for improved efficiency and/or reduced emissions from the engine. The angular position of the crankshaft and camshafts can be determined by affixing a dipole magnet to each of them such that the magnet field of the magnet rotates with the rotating member and then placing a angular position sensor adjacent each rotating member to detect the rotation of each magnetic field. In another embodiment, the angular position of each end of at least one of the rotating members is determined to allow the processor to determine the torsional deflection of the member and the engine controller system is responsive to that determined deflection to further alter operation of the engine.