A method for safely capturing an engine RPM threshold in a spark-ignition internal combustion engines which may exceed the maximum safe unloaded RPM for that engine. Typical engines having a safe RPM high speed redline when coupled to a load, and a reduced RPM redline when decoupled and unloaded, can be set to activate ancillary equipment at a high redline, engine loaded RPM by deriving and processing data from the engine at a low, unloaded reduced RPM speed. The method requires operator reference to an existing OEM or after-market tachometer which enables the user to set a low RPM reference point while the engine is unloaded and running at a slow RPM. Raw data from the latter variable RPM threshold selected by a user is safely captured while the engine is operating unloaded, and a higher RPM threshold is calculated and set from the raw data. The higher RPM threshold may exceed the maximum safe unloaded RPM for said engine.

A method of determining a sliding camshaft actuator pin position based on engine crankshaft angle includes commanding a sliding camshaft actuator to perform a valve step shift, and monitoring an actuator's pin position during the valve step shift command. At least one crank angle is measured when the actuator pin position reaches or exceeds at least one predetermined pin position threshold and at least one remedial action is performed when the actuator pin position does not correlate to the at least one measured crank angle.

An engine synchronization apparatus includes: a crank shaft position sensor detecting a position of a crank shaft to detect a tooth and a missing tooth; a cam sensor detecting a position of a cam corresponding to an angle of rotation of each of an intake cam and an exhaust cam; and a controller synchronizing the engine to use a tooth detection signal from the crank shaft position sensor and a cam signal from the cam sensor. The controller carries out an engine synchronization by determining the position of the crank shaft and the position of the cam to select one cam between the intake cam and the exhaust cam and to detect the position of a unique part of the cam signal from a voltage level and a level length of the cam signal of the selected cam.

An engine synchronization apparatus includes: a crank shaft position sensor detecting a position of a crank shaft to detect a tooth and a missing tooth; a cam sensor detecting a position of a cam corresponding to an angle of rotation of each of an intake cam and an exhaust cam; and a controller synchronizing the engine to use a tooth detection signal from the crank shaft position sensor and a cam signal from the cam sensor. The controller carries out an engine synchronization by determining the position of the crank shaft and the position of the cam to select one cam between the intake cam and the exhaust cam and to detect the position of a unique part of the cam signal from a voltage level and a level length of the cam signal of the selected cam.