The PCM receives signals from various sensors throughout the engine, such as:
* Throttle Position Sensor (TPS): Indicates how much the throttle is open, correlating to engine load.
* Mass Airflow Sensor (MAF) or Manifold Absolute Pressure (MAP) Sensor: Measures the amount of air entering the engine. The B2600I likely uses a MAF sensor.
* Crankshaft Position Sensor (CKP): Tells the PCM the position of the crankshaft, enabling precise timing of fuel injection.
* Camshaft Position Sensor (CMP): Provides information about camshaft position for more precise fuel delivery and ignition timing.
* Oxygen Sensor (O2): Monitors the exhaust gases to check for proper air/fuel mixture. This provides feedback to the PCM to adjust fuel delivery for optimal combustion.
* Engine Coolant Temperature (ECT) Sensor: Informs the PCM of engine temperature, which affects fuel delivery.
Based on the information from these sensors, the PCM calculates the required amount of fuel and precisely times the opening and closing of each fuel injector. The PCM sends a short electrical pulse to the injector's solenoid, opening it and allowing fuel to spray into the intake manifold. The duration of this pulse determines the amount of fuel injected. The process repeats many times per second, constantly adjusting fuel delivery to maintain the optimal air/fuel ratio. This system is often referred to as a "pulse width modulation" (PWM) system.
