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Home >> Honda >> 1987 >> Prelude Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI Electronic Control System >> Description & Operation >> Control Devices >> Main Relay
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Main Relay

One half of main relay is used by ECU to power electric fuel pump. ECU provides a ground for this part of relay when ignition is first turned on (2 seconds), or when an RPM signal is received by ECU (Cranking or running). The second half of the main relay provides power from ignition for the ECU, injectors and power for the fuel pump part of relay.

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