LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volvo >> 1974 >> 164 Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Fuel Delivery >> BOSCH AFC/MPC Fuel Injection Systems >> Operation >> Dual Relay
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Dual Relay

The dual relay is composed of 2 relays which control current supply for entire electronic fuel injection system and which disengages system (electrically) from battery when ignition is turned off. When ignition switch is on, the main relay points close, providing voltage to the ECU and pre-resistors (if used) of the electronic fuel injection system.

Fig 1: Distributor & Triggering Contacts
G09326864Courtesy of NOT AVAILABLE

The other relay within the dual relay, controls current to the electric fuel pump. These points close during cranking and when points of air flow valve are closed. This design is to cut off current to fuel pump in the event that engine stops (airflow meter closed).