The turbocharged and non-turbocharged Multi-Point Electronic Fuel Injection (MPI) system combines an electronic fuel and spark advance control system with a turbocharged intake system or cross type intake system. At the center of this system is a digital computer containing a microprocessor known as an engine controller that regulates ignition timing, air/fuel ratio, emission control devices, idle speed, cooling fan, charging system, turbocharger waste gate (on turbocharged models) and speed control. This component has the ability to update and revise its programming to meet changing operating conditions.
Various sensors provide the input necessary for the engine controller to correctly regulate fuel flow at the fuel injectors. These include the manifold absolute pressure, throttle position, oxygen sensor, coolant temperature, charge temperature, vehicle speed (distance) sensors and detonation sensor. In addition to the sensors, various switches also provide important information. These include the neutral-safety, air conditioning clutch switch, brake switch and speed control switch.