Replacing a Fuel Pump in a Nissan Questby Don Bowman
Introduction and Diagnosis
Before replacing the fuel pump, make sure the fuse to the pump is good and the relay is working. If there are two identical number relays in the relay box, switch the relays. Some years are the same. If not, test the relay by putting power to the switch side of the relay and ground the side marked for ground; it should click as it activates. If not, replace it. If the fuse and the relay are good, disconnect the harness at the fuel pump and have a helper toggle the ignition switch on and off every 5 seconds and check the harness for power. If there is no power, there is a problem with the wiring to the pump or a security problem with the alarm.
Removing the Fuel Pump
To remove the fuel pump, raise and support the vehicle on jack stands. Remove the hose clamps on the fuel filler tube and the overflow smaller hose. Remove the harness connector to the fuel pump. Support the fuel tank and remove the bolts holding the straps around the fuel tank. Bend the straps out of the way, lower the fuel tank and work the filler hose off the neck on the tank as its lowered. Bring it down just enough to remove the fuel pump hoses on the top of the tank. Lower it the rest of the way and remove it from under the vehicle. Using a hammer and screwdriver, tap the fuel pump cap loose and remove it. Remove the fuel pump carefully so as not to damage the fuel sending unit inside the tank. As the fuel pump is removed from the tank, tip it enough to get the sending unit out. Pull the electrical connectors off the fuel pump and loosen the clamp on the short 1-inch hose. Lift the pump up slightly in its housing. Pull the bottom of the pump outward and then down, pulling it out of the hose.
Installing the New Fuel Pump
Install the new fuel pump with a new hose and base rubber gasket that it sits on. Line the top of the hose with the tube that it fits on and push upward, forcing the hose on the tube. While pushing upward, also push the bottom of the fuel pump in and seat it in the housing on top of the rubber gasket. Install the plastic clamps to the short hose and tighten them. Install the electrical connectors in the right polarity. Install the new filter to the bottom of the fuel pump. Install the new seal to the top opening in the tank and insert the fuel pump. Be careful with the sending unit on the fuel pump. Do not bend or distort it, or the fuel gauge will not function. Tip the fuel pump as it is installed to get the sender in. Situate the pump correctly so that the hoses are pointed in the same direction they were when they came off. Install the cap over the fuel pump and screw it on. Raise the tank and connect the fuel lines. Install the metal straps and insert the bolts to hold it in. Connect the harness connector to the fuel pump and tighten the clamps on the filler and overflow hoses.
Don Bowman has been writing for various websites and several online magazines since 2008. He has owned an auto service facility since 1982 and has over 45 years of technical experience as a master ASE tech. Bowman has a business degree from Pennsylvania State University and was an officer in the U.S. Army (aircraft maintenance officer, pilot, six Air Medal awards, two tours Vietnam).