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

1. Remove the Multipoint Fuel Injection (MFI) relay.
2. Check the continuity between the MFI relay terminals.

Inspection terminals 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 System Voltage
Disconnected 0 Volts






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 (O ohms) Continuity (O ohms)
Disconnected No continuity (infinite) No continuity (infinite)

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