be used the engine portion illustrated in fig1 also illustrates an intake cam phaser 18 and an exhaust cam phaser 16 each cam phaser 16 18 allows the ecu to modify the rotational position of the respective cam shaft relative to the crank shaft allowing the opening and closing of the intake and exhaust valves to be varied which changes the air flow characteristics of the engine 2 one function of the ecu 20 fig2 is to act as a feedback controller utilizing a proportional integral derivative pid method to provide a predetermined combustion level using data from the sensor 14 along with data from the intake cam sensor 22 fig2 exhaust cam sensor 24 fig2 and crank shaft position sensor 26 fig2 the ecu can manipulate the phasers 16 18 to change the engine 39 s air flow characteristics in addition to the variable valve timing system the ecu controls other systems not shown to provide a predetermined combustion level while both intake and exhaust cam phasers 16 18 are shown the method disclosed herein does not require both and is applicable to engines with a variety of variable valve timing systems fig2 illustrates a front view of a portion of the engine 2.