Main Relay (Computer/Fuel System): Testing and Inspection

Harness Inspection Using Voltmeter




Step 1 of 5




Step 2 of 5




Step 3 of 5




Step 4 of 5




Step 5 of 5

Relay Inspection Using Voltmeter





1. Remove the Multiport Fuel Injection (MFI) relay and check for continuity between the MFI relay terminals.
Terminals (5) - (7): Continuity
Terminals (6) - (8): Continuity in one direction




2. Using jumper wires, connect terminal (7) of the MFI relay to the positive battery terminal and connect terminal (5) of the relay to the negative battery terminal.

CAUTION: When connecting the jumper wires, be careful not to connect them to the wrong terminals, since this could damage the relay.

3. Measure the voltage at terminal (1) of the MFI relay while connecting and disconnecting the jumper wire to the negative battery terminal.
Voltage at terminal (1):
Jumper Wire Connected: Battery voltage
Disconnected: 0 Volts




4. Using jumper wires, connect terminal (8) of the MFI relay to the positive battery terminal and connect terminal (6) of the relay to the negative battery terminal.
5. Check for continuity between terminal (2) and terminal (4), and terminal (3) and terminal (4) of the MFI relay while connecting and disconnecting the jumper wire and the negative battery terminal.
Jumper Wire Connected: continuity between terminals (2) and (4), also continuity between terminals (3) and (4).
Disconnected: No continuity between the above terminals.

6. If there is an incorrect condition replace the MFI relay.