System Description

Fuel injectors are solenoid operated valves, located on intake manifold, one for each cylinder. When a fuel injector solenoid is energized (pulsed) injector needle valve opens, allowing pressurized fuel to pass through injector and mix with air entering engine. Engine Control Module (ECM) controls injector timing and pulse width. ECM pulses fuel injectors based on information provided by its network of engine sensors. ECM uses crankshaft position sensor to determine when to pulse injectors. Engine coolant temperature, intake air temperature, air flow and throttle position data are all used by ECM to calculate injector pulse width. ECM also uses its network of sensors to determine whether all injectors should be pulsed at same time (simultaneous injection) or each injector should be pulsed individually (sequential injection). Sequential injection is almost always used during normal engine operation. Simultaneous injection may be used when engine is being cranked.