Main Relay (Computer/Fuel System): Description and Operation

Fig. 33 Multi-Port Fuel Injection Main Relay:

The main relay actually contains two individual relays. This relay is mounted on the left side under-dash.
One relay is energized whenever the ignition is on, and it supplies the battery voltage to the ECU, power to the injectors, and power to the second relay.
The second relay is energized for 2 seconds when the ignition is switched on before starting, and when the engine is running, to supply power to the fuel pump.