Fuel Injection Timing

For fuel injection timing:
- each fuel injector is energized once every other crankshaft revolution in sequence with ignition firing order.
- the period of time that the fuel injectors are energized (fuel injector "on time" or pulse width) is controlled by the vehicle's Powertrain Control Module (PCM).
- air entering the engine is monitored by mass air flow, pressure and temperature sensors.
- the outputs of the electronic engine control sensors are processed by the powertrain control module.
- the powertrain control module determines the needed fuel injector pulse width and outputs a command to the fuel injectors to meter the exact quantity of fuel.