Ignition System: Description and Operation

GENERAL DESCRIPTION
The Multiport Fuel Injection System consists of sensors, actuators and the engine control module (ECM) or powertrain control module (PCM) . The sensors detect the engine condition. The module controls the system based on signals from these sensors. The actuators work under the control of the ECM (or PCM).

The ECM (or PCM) carries out activities such as fuel injection control, idle air control, and ignition timing control. In addition, the ECM (or PCM) has several diagnostic test modes which simplify troubleshooting when a problem develops.

In addition, the ECM (or PCM) is equipped with several diagnostic test modes which simplify troubleshooting when a problem develops.

IGNITION TIMING CONTROL
The ignition power transistor located in the ignition primary circuit turns on and off to control primary current flow to the ignition coil. This maintains ignition timing at an optimum level regardless of various engine operating conditions. The ECM (or PCM) determines the ignition timing according to engine speed, intake air volume, engine coolant temperature, and atmospheric pressure.