NOTE: If the car starts and continues to run, the PGM-FI main relay is OK.
NOTE: Pay close attention to the diodes!!! This just bit me. Power can flow only one way through a diode. The diodes are the triangle arrow looking symbols in the Main relay diagram. The 'arrow' is the direction of current flow from positive to negative. Guess I should of read the directions more closely.
MAIN RELAY TEST
1. Remove the main relay.
2. Attach the positive battery terminal to the #4 terminal and the negative battery terminal to the #8 terminal of the main relay. Then check for continuity between the #5 terminal and the #7 terminal of the main relay.
a. If there is continuity, go to step 3.
b. If there is no continuity, replace the relay and retest.
3. Attach the positive battery terminal to the #5 terminal and the negative battery terminal to the #2 terminal of the main relay. Then check for continuity between the #1 terminal and the #3 terminal of the main relay.
a. If there is continuity, go to step 4.
b.If there is no continuity, replace the relay and retest.
4. Attach the positive battery terminal to the #3 terminal and the negative battery terminal to the #8 terminal of the main relay. Then check for continuity between the #5 terminal and the #7 terminal of the main relay.
a. If there is continuity, the relay is OK.
b. If the fuel pump still does not work, go to harness test.
c. If there is no continuity, replace the relay and retest.
MAIN RELAY HARNESS TEST
1. Keep the ignition switch in the OFF position.
2. Disconnect the main relay electrical connector.
3. Check for continuity between the BLACK wire (pin 2) in the connector and body ground.
Fig. 33 Main Relay Harness Test (pins 1 and 2)
Fig. 34 Main Relay Harness Test (pins 2 and 5)
4. Attach the positive probe of the voltmeter to the YELLOW/WHITE wire (pin 1) and the negative probe to the BLACK wire (pin 2).
a. Battery voltage should be available.
b. If there is no voltage, check the wiring between the battery and the main relay as well as the ECU fuse (15A) in the main fuse box.
5. Attach the positive probe of the voltmeter to the BLACK/YELLOW wire (pin 5) and the negative probe to the BLACK wire (pin 2).
6. Turn the ignition switch ON.
a. Battery voltage should be available.
b. If there is no voltage available, check #14 fuse and the wiring from the ignition switch to the fuse box, and the wiring from the fuse box to the main relay.
7. Attach the positive probe of the voltmeter to the BLUE/WHITE wire (pin 4) and the negative probe to the BLACK wire (pin 2).
Fig. 35 Main Relay Harness Test (pins 2 and 4)
Fig. 36 Main Relay Harness Jumper Test
8. Turn the ignition switch to the START position.
a. Approximately 10 volts should be available.
b. If there is no voltage check the #2 (10A) fuse and the wiring between the ignition switch and the fuse box, and from the fuse box to the main relay.
9. Connect a jumper wire between the BLACK/YELLOW wire (pin 5) and the YELLOW/BLACK wire (pin 7).
10. Turn the ignition switch ON.
a. The fuel pump should work.
b. If the fuel pump does not work, check the wiring between the main relay and the fuel pump, and the wiring from the fuel pump to the ground (BLACK wire).
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See below in main relay pin 2 is ground.
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