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Home >> Honda >> 1994 >> Prelude L4-2.2L SOHC >> Repair and Diagnosis >> Powertrain Management >> Relays and Modules - Powertrain Management >> Relays and Modules - Computers and Control Systems >> Main Relay (Computer/Fuel System) >> Description and Operation
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Main Relay (Computer/Fuel System): Description and Operation



PURPOSE
The Main Relay, located under the left side of the dashboard, supplies power to the Programmed Fuel Injection Electronic Control Module (PGM-FI ECM), injectors and supplies power to the fuel pump for 2 seconds for starting purposes.

OPERATION
The Main Relay, actually contains two individual relays:
^ The first relay is energized whenever the ignition is on, and it supplies the battery voltage to the PGM-FI ECM, 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 also energized when the engine is running, to supply power to the fuel pump.