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

1. Remove the MFI relay.
2. Check the continuity between the MFI relay terminals.

Inspection terminal Continuity
5-7 Continuity (Approx. 90 Ohms)
6-8 Continuity in one direction




3. Use jumper leads to connect MFI relay terminal 7 to the battery (+) terminal and terminal 5 to the battery (-) terminal.

CAUTION: If jumper leads are not connected properly, the relay will be damaged.

4. Check the Voltage at MFI relay terminal 1 while connecting and disconnecting the jumper lead at the battery (-) terminal.

Jumper lead Voltage at terminal 1
Connected Battery Voltage
Disconnected 0 Volt




5. Use the jumper leads to connect MFI relay terminal 8 to the battery (+) terminal and terminal 6 to the battery (-) terminal.
6. Check the continuity between MFI relay terminals 2 - 4 and terminals 3 - 4 while connecting and disconnecting the jumper lead at the battery (-) terminal.

Jumper lead Continuity between Continuity between
terminals 2-4 terminals 3-4

Connected Continuity Continuity
Disconnected No Continuity No Continuity

7. If there is a defect, replace the MFI relay.