The following may help give an idea how the ECM controls the Fuel and Ignition.
Ignition Timing
2013 Shop Manual - Adobe Reader page 289
The Crankshaft Position Sensor (CPS), the Air Pressure Sensor (APS), and the Throttle Position Sensor (TPS) are the primary sensors used to control the Ignition Timing.
The ECM is programmed with data (ignition mappings). Using engine operating parameters provided by the sensors, the ECM controls the ignition timing for optimum engine operation under all operating conditions.
Throttle Position
2013 Shop Manual - Adobe Reader page 237
TPS will determine the basic parameters for all fuel mapping and several ECM calculations for idle speed control of the engine.
e-RAVE
2013 Shop Manual - Adobe Reader page 110
Many different mappings are used by the ECM to control the 3D RAVE valves. The mappings are based on current engine RPM, crankshaft rate of acceleration or deceleration and the following inputs: intake temperature, TPS, knock sensor, engine coolant temperature and APS.
Fuel Injection
2013 Shop Manual - Adobe Reader page 234-235
The ECM reads the input signals from different sensors which indicate engine operating conditions at micro-second intervals.
The ECM calculates the proper air/fuel ratio and activates the output to fuel injectors.
Signals from sensors are used by the ECM to determine the injection parameters (fuel maps required for optimum air-fuel ratio).
The crankshaft position sensor (CPS), the Throttle Position Sensor (TPS) are the primary sensors used to control the injectors. Other sensors (like temperature sensors, etc) are used as secondary input.
2013 Shop Manual - Adobe Reader page 253
The correct matching of the fuel injector and cylinder must be confirmed using B.U.D.S. And incorrect match between the fuel injector and cylinder may lead to engine misfiring, improper idling or poor fuel economy.
NOTE: The engine will be able to run with an improperly matched fuel injector. However, the engine may misfire, run rough at idle, have poor fuel economy or run lean.
2013 Shop Manual - Adobe Reader page 237
The fuel injectors provide a stratified fuel charge to the combustion chamber up to clutch engagement speed. Beyond this RPM, the fuel charge becomes homogeneous.
The stratified fuel charge provides a cleaning combustion , better idling and less smoke.
Idle Speed
2013 Shop Manual - Adobe Reader page 235
The air flow is controlled by two throttle plates. Each throttle plate has a 6,8 mm (0.268 in) idle port in it.
Since there is a constant airflow through the idle ports of the throttle plates, the idle speed is controlled by the ECM by varying the amount of fuel injected in the combustion chamber and by controlling the injection timing.