The Nissan 240SX uses an electric pump located in the gas tank to move fuel to the engine. When you start the car, the pump begins to send fuel through the pressurized lines. If the fuel pump malfunctions, the result will be an engine that runs sluggishly or not at all. Fortunately, Nissan included an inspection port behind the rear seat, which makes removing the fuel tank to replace the fuel pump unnecessary. You should be able to complete the replacement in an hour or less.
Remove the cap from the gas tank to relieve pressure in the tank.
Remove the cover from the fuse panel located below the dash, to the left of the brake pedal, and locate the 15A fuel pump fuse. It should be the third fuse from the bottom in the left column.
Start the car's engine and let it idle until it dies from lack of fuel. Try to start the car again to ensure the fuel lines are clear. Disconnect the negative cable on the battery.
Fold down the rear seat to locate the inspection hole cover. Use a socket wrench to remove the four bolts that hold the cover in place and remove the cover.
Disconnect the wiring harness connector and the fuel line from the fuel pump's upper plate. The wiring connector is held in place with a plastic tab. The fuel line has a tab on each side you must depress to separate the two ends.
Remove the lock nut by unscrewing it counterclockwise. For best results, use Nissan special tool #SST J38879-A to avoid damaging the lock nut. If this tool is not available, use a pair of large vise grips to turn the lock nut, being careful not to deform it.
Lift the old fuel filter out of the tank. If the tank still contains a high level of fuel, expect some gasoline to drip from the pump.
Insert the new fuel pump assembly into the inspection hole. Make sure the arrow on the top plate points towards the index marks on the rear-passenger's side of the fuel tank. Replace the lock nut.
Attach the fuel line and the harness electrical connector. Replace the inspection hole cover, ensuring the arrow points towards the front of the car, and insert the four bolts.
Reconnect the negative battery cable and replace the fuel pump fuse. Replace the gas cap.
Turn the ignition switch to the "On" position, pause a few seconds, and turn it off. Repeat this step three times, to prime the fuel system with gasoline, and start the vehicle.
