General System Description

Fig. 11 PGM-FI electronic controls:

Fig. 12 PGM-FI electronic controls:

Fig. 13 PGM-FI electronic controls:

Fig. 14 PGM-FI electronic controls:

The Programmed Fuel Injection (PGM-FI) System is an electronically controlled multi-point fuel injection system that consists of three major sub-systems: Air Intake and Idle Control System, Electronic Control System and Fuel System. The electronic control system provides centralized microprocessor control over the fuel and air intake systems, and provides a self-diagnostic function to aid in diagnosing system malfunctions.
When the ignition switch is turned to the run position, the ECU supplies a ground to the main relay. This causes the fuel pump to run for two seconds, thus pressurizing the fuel system.
When the engine is cranking or running, the ECU receives a signal from the crank angle sensor. Once the ECU knows the engine is turning, it supplies the ground to the main relay to keep the engine running.
With the ignition switch in the run position, the main relay also supplies voltage to each fuel injector through a dropping resistor. Once the ECU decides how long it wants each injector to stay open (after sampling a variety of sensors, such as air and coolant temp. and engine speed and load) it grounds each injector for the proper duration.