If an electric fuel pump is not working, is not delivering enough fuel pressure to meet specifications, or is not pumping enough fuel volume to keep up with the engine's needs, the pump may need to be replaced. But before that happens, you should rule out all the other possibilities such as a plugged fuel filter, restricted fuel line, bad fuel pressure regulator, bad fuel pump relay, or fuel pump wiring problem. If all of these have been checked and eliminated, you can go ahead and replace the pump.

NOTE: The Fuel Pump Manufacturers Council says many fuel pumps are replaced unnecessarily or are returned under warranty because the fuel pump was not correctly diagnosed. So save yourself the time and trouble and make sure the pump is really bad before you buy a replacement pump.

In-Tank Electric Fuel Pump Replacement

WARNING: Gasoline is extremely flammable. Do not smoke when working on the fuel system, and keep any sparks or other sources of ignition away from the vehicle and fuel tank. Do NOT use an incandescent trouble light near the fuel tank as the hot surface of the light bulb can ignite any fuel that might spill or splash on it. Fuel vapors are heavier than air and can also travel a long distance along a garage floor. The fumes can be ignited by a heater, pilot light, electric motor or other source of ignition some distance away. Also be aware of the fact that static discharges can also ignite fuel. Proceed with caution.

Before unbolting the straps that secure the fuel tank in place, remove as much fuel as possible from the tank. This will lighten the tank considerably and make it much easier to handle, lower and lift back into place. Some gas tanks have a drain plug in the bottom, but most do not so you will have to use a hand siphon pump to drain the tank (do NOT use an electric drill powered pump as the sparks may ignite the fuel!). Insert the hose down the filler neck and use the hand pump to start the siphon action. Do NOT suck on the hose to start a siphon because gasoline is poisonous and the fumes can harm your lungs. Drain the fuel into an approved container (a metal or plastic gas can, NEVER an open bucket), and seal the container once all the fuel has been drained from the tank. Do NOT leave open containers of gasoline sitting around.

Make sure the parking brake is set, the transmission or transaxle is in park, and the front wheels are chocked with blocks or bricks so the vehicle can't roll when you raise it. The vehicle should also be parked on a level surface.

Raise the rear of the vehicle as needed with a jack, and support the vehicle with a minimum of two jack stands (make sure the stands have the proper weight rating to handle the weight of the vehicle). NEVER crawl under a vehicle that is only supported by a jack.

Disconnect the filler neck from the fuel tank by loosening or removing the clamp that holds the hose on the tank.

Remove either the front two bolts or the rear two bolts that secure the fuel tank straps to the vehicle. Then gently lower one end of the tank. This will allow you to reach the wiring connections, fuel line and vent hoses on top of the tank. Disconnect the wires and hoses before removing the two remaining bolts that hold the other end of the straps. The tank can now be lowered from the vehicle.

Once the tank is sitting on the ground, you can undo the plate on the top of the tank the holds the fuel pump in place. The plate may have a metal ring that has to be rotated counterclockwise to remove the ring. Or, the plate may be held in place with screws or bolts. Once this plate has been loosened, the plate, fuel pump and sending unit can be carefully pulled out of the tank.

Pump and Tank Inspection

When you install the pump in the tank, put a new filter screen on the pump (a new screen usually comes with the pump). A new gasket or seal should also be installed on the top plate to prevent leaks. If the fuel line or vent hoses are old and cracked, they should be replaced also.

Raise the tank high enough so the fuel pump wires, fuel line and vent hoses can be reconnected, then finish raising it and install the support straps to hold the tank in place.

Reconnect the fuel filler tube, then add fuel to the tank and check for leaks. The tank should be at least 1/4 full to provide enough fuel for proper fuel pump lubrication and cooling.

Replacing the fuel filter at this time is also recommended.

Start the engine and check again for any leaks. No leaks? Great, you're done.