Abstract: A method of calibrating the timing of a fuel injected engine using the outputs of first and second position detectors both of which develop signals representing the position of a piston in a cylinder includes the steps of operating the engine using a first reference timing value to determine the time at which a fuel injector is actuated, determining from the output of the second position detector a measured time value representing the length of time between actuation of the fuel injector and the time at which the piston reaches a certain position in the cylinder and subtracting from the measured time value an offset value representing the length of time between actuation of the fuel injector and the actual beginning of fuel injection to obtain an actual timing value. A second reference timing value is calculated from the first reference timing value, the actual timing value and a desired timing value and is subsequently used to determine the time at which the fuel injector is thereafter actuated.

Abstract: An apparatus (10) for use on electronically controlled fuel injection systems senses speed, angular position, and direction of rotation using only a single Hall effect type sensor (24). A disk element (14) is fixedly connected to and rotatable with the camshaft of an internal combustion engine. The disk element (14) includes a plurality of circumferential zones (16a-16x) of substantially identical length with each zone (16a-16x) having first (18a-18x) and second (20a-20x) areas. A first portion 16c-16t, 16v-16x) of these circumferential zones (16a-16x) have first (18c-18t, 18v-18x) and second areas (20c-20t, 20v-20x) which are substantially different in length than the first (18a, 18b, 18u) and second areas (20a, 20b, 20u) of a second portion ( 16a, 16b, 16u) of the circumferential zones (16a-16x).