Comanche 4WD L6-242 4.0L VIN L FI (1990)
from the ECU to the fuel pump relay should be present. If voltage is present proceed to step 4. If no voltage is present, disconnect the 24-Way
and 32-Way ECU connectors, and the fuel pump relay. Connect an ohmmeter between the F17 (terminal 86) wire and the OR/WT wire at pin
connector no. A7 of the ECU, and check for continuity. If continuity exists, the problem is computer related.
If no continuity exists, repair open in wire, reconnect ECU and fuel pump relay, and test operation.
4.
Connect voltmeter to 11 (terminal 85) wire at fuel pump relay connector. Turn ignition key to START position, and crank engine, while observing
voltage at 11. Voltage should be present at 11 and drop to less than 1 volt within 2 seconds during cranking. If voltage drops fuel pump relay is
functioning, and no further testing of the fuel pump relay is necessary. If voltage does not drop, proceed to step 5. If no voltage is present,
disconnect the fuel pump relay, and connect an ohmmeter between the F17 (terminal 86) and 11 (terminal 85) of the fuel pump relay and check for
continuity. If no continuity exists replace the fuel pump relay and test operation.
5.
Disconnect the 24-Way and 32-Way ECU connectors, and the fuel pump relay. Connect an ohmmeter between the 11 wire at the fuel pump relay
connector and the yellow wire at pin connector no. B8 of the ECU. Check for continuity. If no continuity exists repair open in wire, reconnect
ECU and fuel pump relay, and test operation. If continuity exists, the problem is computer related.
