How to Change a Fuel Sending Unit

The fuel sending unit in your vehicle is often connected to the fuel pump inside your gas tank. The sending unit contains a device that measures the amount of gasoline in the tank via a float attached to the unit. The amount of gasoline in your gas tank will cause the float to go up or down. When a sending unit malfunctions, you will find it difficult or impossible to know how much gas is in your gas tank. At this point, it's time to change the fuel sending unit.

Things You'll Need

• Jack 2 jack stands Suction pump Container for gasoline Socket wrench and socket set Screwdriver Tire wrench Torque wrench Shop rags

Instructions

1. Loosen all of the lug nuts on both of the rear wheels by turning them 1/4 turn counterclockwise with the tire wrench.

2. Pull the fuse inside the vehicle for the fuel pump.

3. Turn the vehicle on and wait for the vehicle to stall out. The pressure in the fuel system has now been relieved, so it will be safe to work on it.

4. Jack the vehicle up with the floor jack using the rear jack point. This will be located near the trunk area and will be either the frame or an extension of the frame. Then, place the jack stands under the rear pinch welds of your vehicle and lower the vehicle onto the jack stands.

5. Detach the cable from the negative battery terminal. To do this, turn the retaining bolt on the cable clip counter-clockwise until the clip loosens enough for you to remove it.

6. Drain the gasoline from the gas tank. You will only need to do this if your sending unit is located inside the fuel tank. To drain the fuel tank, open the gas tank door, remove the filler cap and place the hose of the suction pump down into the gas tank. Pump the gasoline out of the tank and into a container that's approved for holding gasoline.

7. Disconnect the fuel lines from the pump. These are usually hose clamps, but may be tube nut connectors. For host clamps, you can unscrew the clamp with a screwdriver. For tube nuts, you will need an open-ended wrench.
   If your fuel pump is inside the gas tank, there will be a portion of the pump sticking out of the tank. Disconnect the electrical connections going into the pump. You also may have to remove the gas tank. To remove the gas tank, unbolt the two straps holding the tank in place, and then unbolt all of the bolts around the tank, holding the tank to the vehicle's body. Then lower the tank to the ground so that you can work on it.

8. Remove the fuel pump cover and any brackets attached to the fuel pump assembly.

9. Unbolt the bolts on the fuel pump mounting bracket and remove the fuel pump from the gas tank. The sending unit will be attached to the fuel pump.

10. Separate the fuel pump from the fuel sending unit (this will vary depending on your vehicle and how the manufacturer attaches the two components). On some vehicles, the pump and sending unit must be replaced together.

11. Install the new sending unit and reassemble the fuel system, making sure that you reconnect the battery cable. Installation is the reverse of removal.

12. Pressurize the fuel system. Make sure that the fuse for the fuel pump is replaced in the fuse box, and turn the vehicle on. The system is now pressurized.

13. Put the wheels back on the vehicle and tighten the lug nuts.

14. Lower the vehicle to the ground and torque the lug nuts to 100 foot-lbs using the torque wrench.

References

• Automotive Shop (service) Manuals - More Information About Changing a Fuel Sending Unit For Your Vehicle