The 1998 Jeep Wrangler's engine receives fuel from the fuel tank by means of an electrically powered fuel pump assembly located in the fuel tank. The assembly also contains the fuel filter and the fuel level sending unit. If fuel isn't making it to the engine, first check the fuel pump relay in the power distribution center. If the relay is fine, you should suspect a faulty fuel pump. Since you must remove the fuel tank to access the fuel pump, this procedure will take at least a couple of hours and will require the help of an assistant.
Remove the fuel tank cap. Insert a plastic object, such as an ink pen, into the tank opening to force open the metal flap, relieving pressure in the tank. Do not use anything metal as this can cause sparks. This flap is a secondary backup to ensure vapors don't leak from the tank. Leave the gas cap off.
Open the hood and locate the power distribution center near the battery. Remove the cover and check the diagram inside it for the location of the fuel pump relay. Remove the relay from its slot.
Start the vehicle and allow it to run until it dies. Attempt to start the vehicle again. If it will not start, all fuel pressure has been released.
Use a socket wrench to disconnect the negative battery cable to prevent sparking.
Remove the eight screws that secure the fuel filler bezel to the vehicle's body with a Phillips head screwdriver then remove the bezel.
Cut the plastic zip tie that secures the rear axle vent hose to the fuel filler hose.
Disconnect the fuel pump electrical connector located on the front left-hand side of the fuel tank. This is a plastic connector with tabs on each side that you must lift to disconnect it.
Remove the rubber EVAP hose from the EVAP inlet. The hose is located near the electrical connector and simply slides off the inlet.
Disconnect the fuel line quick connector by squeezing the tabs on each side while you pull the connector apart. The fuel line is located adjacent to the EVAP hose at the front of the tank.
Position a floor jack beneath the fuel tank/skid plate assembly. Raise the jack until it supports the tank. You will need an assistant to help you control the tank when you remove it.
Remove the three skid plate nuts at the front of the tank and the four skid plate nuts at the rear of the tank with a socket wrench. Lower the tank and slide it out from under the vehicle with the help of your assistant.
Use clean rags and water to clean the area around the fuel pump module on the top of the tank to prevent contamination when you remove the pump.
Attach a special lock nut tool to the plastic nut around the fuel pump assembly and rotate it clockwise to remove. You can also use a pair of large vise grips to remove the nut, but it's easy to damage it in this manner.
Pull the old pump module from the fuel tank.
Insert the new module into the fuel tank, making sure to use the new rubber gasket included with the new pump. Verify that the arrow on the top of the module is pointed toward the front of the vehicle.
Install the plastic lock nut and tighten it to 45 ft.-lbs. with the special tool and a torque wrench.
Rotate the fuel filter assembly in the top of the pump until it is pointed to the 10 o'clock position in relation to the arrow.
Position the tank under the vehicle and raise it into place with the floor jack. Replace the four rear and three front nuts. Tighten the nuts to 141 ft.-lbs. of torque. Remove the floor jack.
Reconnect the electrical connector, EVAP hose and quick connect fuel line.
Secure the rear axle vent hose to the fuel filler with a new plastic zip tie.
Position the filler hose in place and re-attach the bezel with the eight screws. Replace the fuel cap.
Reconnect the negative battery cable and replace the fuel pump relay in the power distribution center.
Turn the ignition on, pause a few seconds then turn it off. Repeat this three times to prime the fuel system. Start the vehicle and check for leaks around the gas tank. If the "Check Engine Light" comes on, ensure the fuel cap is secure.
