Fuel Sending Unit
The fuel sending unit in your vehicle is ultimately how you are able to tell how much fuel you have at any given time. It is associated with the fuel gauge which is regulated by something called a “variable resistor” and it helps you to monitor the fuel levels of your vehicle at any given time. You will find that there are two main types of fuel sending units. The first type used to be common in aspirated vehicles which had a fuel sending unit that was completely separate from the actual fuel pump module. Today most fuel injected cars have fuel sending units which are part of the fuel tank, so they are essentially combined. Essentially the fuel sending unit looks like a plunger and there are a number of things you will want to consider when purchasing and installing one of these in your vehicle. Those who are not familiar with this process will certainly want to learn all they can before beginning, because it can be a somewhat complex and involved process.
Those who do not have a natural flare for working on cars might want to check their vehicle’s manual before getting started so you will be able to easily locate the fuel pump relay. Once you have found it you will then want to remove it and start up the vehicle, waiting until it turns off completely. After you have gone through this step you will be able to replace the fuel pump relay. It will then become necessary to completely disconnect the negative battery cable so you will be able to ensure that sparks will not become a problem while you are working. Because you are working with fuel, even the smallest spark can have disastrous consequences, so it is important to make sure you disconnect the negative battery cable.
The next step will involve emptying out the fuel tank with a pump that has been designed to siphon out fuel; it should have a fuel container on the other end so it will not simply leak out when you it is being siphoned. You should not have any trouble with locating the fuel sending unit. In most vehicles there is usually an access cover above it, acting as a form of protection for this part. Some people with certain vehicles might need to remove their backseat in order to access the fuel sending unit. You will need to unscrew the screws on the access cover so you will be able to gain access to the unit. After you have done this it will then be necessary to jack up your vehicle, making sure that the floor jack is directly underneath the gas tank so it will have plenty of support while you are working.
You will need to have a ratchet as well as an extension and socket to remove the mounting bolts on the straps of the tank, so make sure you have them at the ready when you are preparing to access it. The next step will consist of lowering the tank down ever so slightly, pressing the lock tabs which are on the plastic hose connectors, effectively removing the lines as well as the hoses from their fittings. For the next step you will need to unplug the electric connector for the pump and completely lower the tank down to the floor. It will then become necessary to disconnect the fuel sending unit and there are multiple ways you can go about doing this.
To disconnect the fuel sending unit you will be able to use a drift punch as well as a hammer or simply a flathead screwdriver on the notches which are found along the outer ring of the unit which will work just as well. You will find that the fuel sending unit will be attached to a rather long rod which has a float on the very end, which can make removing it somewhat of a challenge depending on whether or not you have experience doing this. Although you may have to do a little bit of maneuvering at first, you will be able to get it out and remove the rubber seal as well as the fuel pump from the current sending unit.
After you have managed to secure the new unit which you are putting in, you will have to use the jack to raise it back up to plug it in to the electrical connector. Then you will be able to attach the fuel lines as well as all of the hoses back to the new fuel sending unit, raising it up until it has been properly seated which is when you will be able to put the mounting bolts back on the straps.