Replacing Bmw Fuel Sensor: Step-By-Step Guide For Diyers

Owning a car is a big responsibility. One of the most important things to keep an eye on is the fuel sensor. If your BMW's fuel sensor is faulty, you may experience difficulty starting the engine or poor performance that could cause trouble in traffic. Luckily, replacing the fuel sensor yourself is a fairly simple task.

First, run the fuel almost empty. Then, unplug the negative battery cable, remove the back seat, and the rubber cover over the fuel tank on the side you are replacing. Next, remove the round rubber plug underneath the first layer of the rubber pad, followed by the 10mm nuts on the round metal plate over the fuel pump. Now, simply unplug the electric connector and remove the black fuel line connector gently by squeezing the side tabs. Be sure to have paper towels on hand to absorb any gasoline spillage.

The next steps involve removing the blue fuel line and holding down the white tab facing the front of the car with a large screwdriver so the fuel pump does not turn. Then, use another large flat screwdriver and a rubber mallet to unscrew the metal ring holding the fuel pump in the tank. Hit it counterclockwise. Once the metal ring is loose, remove and lift the top of the fuel pump off to the side, still connected. Finally, reach into the tank, pull up on the fuel sender, and unplug it from the fuel pump. There are two tabs on either side that you just need to squeeze and pull upward.

Now, all that's left to do is replace it with a new fuel sender, which will have a slot that it snaps down into, going in only one direction. Pay attention to what it looked like before you removed it. Then, simply reassemble everything in reverse. And there you have it—you've replaced your BMW's fuel sensor!

Disconnect the battery and run the fuel tank almost empty

Disconnecting the battery and running the fuel tank almost empty are the first two steps in replacing a BMW fuel sensor. Here is a detailed, step-by-step guide on how to perform these initial procedures safely and effectively:

Disconnecting the Battery:

• Locate the negative battery cable. This is usually a black cable with a minus (-) sign.
• Unplug the negative battery cable from the battery terminal. This will disconnect the power supply to the vehicle's electrical system.
• It is important to note that modern BMWs have complex electrical systems, and disconnecting the battery can cause certain modules to lose their memory or require reset procedures. Ensure you have the necessary tools and knowledge to perform this step.

Running the Fuel Tank Almost Empty:

• After disconnecting the battery, you will need to run your BMW until the fuel tank is almost empty. This is a crucial step as it ensures that the amount of fuel remaining in the tank is minimal, reducing the risk of fuel leakage and potential safety hazards during the sensor replacement process.
• Drive your BMW until the fuel gauge reaches the lowest possible level, ideally below a quarter tank.
• Be mindful of your remaining fuel range and plan your route accordingly to avoid running out of fuel during this step.
• Once the fuel level is sufficiently low, park your vehicle on a level surface and engage the parking brake.

At this point, you have successfully completed the first two critical steps in replacing your BMW fuel sensor. It is important to exercise caution and follow safety protocols when working with fuel systems. Now you can proceed to the next steps in the sensor replacement process, which may include removing interior components, accessing the fuel tank, and performing the physical replacement of the sensor. Always refer to a reliable repair manual or seek professional assistance if you are unsure about any part of the procedure.

Remove the back seat and rubber cover over the fuel tank

To remove the back seat and rubber cover over the fuel tank of your BMW, follow these steps:

First, run the fuel in the tank almost empty. Next, disconnect the negative battery cable. Now, you can remove the back seat. Simply pull up on the seat firmly and it should come away.

With the back seat removed, you will now be able to access the rubber cover over the fuel tank. Remove this rubber cover. You should now see a round rubber plug underneath the first layer of the rubber pad. Remove this rubber plug.

Now, you will be able to see the metal plate over the fuel pump. Remove the 10mm nuts holding this in place, and then remove the plate.

Disconnect the electric connector and remove the fuel line connectors

Disconnecting the electric connector and removing the fuel line connectors is a crucial step in replacing a BMW fuel sensor. Here is a detailed, step-by-step guide to help you through the process:

Step 1: Prepare the Workspace

Before beginning any work on your BMW's fuel system, it is essential to ensure your safety and that of your vehicle. Park the car on a level surface and engage the parking brake. For this job, you will need to access the fuel tank, so make sure you have a jack and jack stands to safely lift the vehicle. Place wheel chocks around the wheels for added security. It is also recommended to wear safety goggles and gloves to protect your eyes and hands.

Step 2: Disconnect the Battery

Locate the negative battery terminal and disconnect it using an appropriate socket or wrench. This step is crucial to prevent any accidental electrical shorts during the fuel sensor replacement process.

Step 3: Access the Fuel Tank

To reach the fuel sensor, you will need to access the fuel tank. This typically involves removing the rear seat of your BMW. Firmly pull up on the seat to remove it. Be careful not to damage any trim pieces or wiring during this process. Once the seat is removed, you will have access to the fuel tank.

Step 4: Locate the Fuel Sensor

The fuel sensor is usually located on the top of the fuel tank and is connected to the fuel pump. It may be covered by a rubber cover or mat, which you will need to remove carefully. In some BMW models, there may be multiple fuel sensors, so ensure you identify the correct one.

Step 5: Disconnect the Electric Connector

Now, locate the electric connector that powers the fuel sensor. It is important to disconnect this before removing any fuel lines to avoid any electrical issues. Gently unplug the electric connector. You may need to wiggle it slightly to detach it, but be careful not to force it, as this may damage the connector.

Step 6: Remove the Fuel Line Connectors

The fuel sensor is connected to the fuel lines, which supply fuel to the engine. To remove the fuel sensor, you will need to detach these fuel lines carefully. There are usually two fuel line connectors: a black one and a blue one. Gently squeeze the side tabs on the black fuel line connector to remove it. Have paper towels or a suitable absorbent material ready, as some fuel may leak out.

Next, remove the blue fuel line connector by squeezing the connector sides. Again, be prepared for some fuel to leak out, and have absorbent material ready. You may need to remove this connector several times to completely bleed off the pressure in the fuel line. It is crucial to perform this step carefully and avoid any open flames or cigarettes during this process, as you are working with flammable gasoline.

By following these steps, you will have successfully disconnected the electric connector and removed the fuel line connectors, allowing you to proceed with the next steps in replacing your BMW's fuel sensor. Remember always to work safely and refer to a trusted repair manual or a mechanic if you have any doubts.

Remove the metal plate and fuel pump

To remove the metal plate and fuel pump, follow these steps:

First, remove the back seat of your BMW. This is done by pulling up on the seat firmly. Next, remove the rubber cover over the fuel tank on the side you are replacing. Then, remove the round rubber plug underneath the first layer of the rubber pad. Now, you can remove the four 10mm nuts on the round metal plate over the fuel pump. Once these are removed, simply take off the metal plate.

At this point, you will be able to access the fuel pump. To remove it, first, unplug the electric connector. Then, remove the black fuel line connector by gently squeezing its side tabs. Have some paper towels ready to absorb any gasoline that leaks out. Next, remove the blue fuel line in the same way as the black one. Again, be prepared for gasoline to leak out. You will need to do this several times to bleed off the pressure. Now, have someone hold down the white tab facing the front of the car with a large screwdriver so that the fuel pump does not turn.

You are now ready to remove the fuel pump. Use another large flat screwdriver and a rubber mallet to unscrew the metal ring holding the fuel pump in the tank. Hit it counterclockwise. Once the metal ring is loose, remove it, then lift the top of the fuel pump off and place it to the side, still connected.

Replace the fuel sensor and reassemble

To replace the fuel sensor and reassemble, follow the steps below:

Firstly, run the fuel almost empty. Then, unplug the negative battery cable. Next, remove the back seat. Simply pull up on the seat firmly. After that, remove the rubber cover over the fuel tank on the side you are replacing. Remove the round rubber plug underneath the first layer of the rubber pad.

Now, remove the 10mm nuts on the round metal plate over the fuel pump and remove the plate. Then, unplug the electric connector. Remove the black fuel line connector gently by squeezing the side tabs. Have paper towels to absorb any gasoline. Remove the blue fuel line by squeezing the connector sides. Remove it just enough to bleed off pressure. Some gasoline will come out so have paper towels around it. You may have to do this several times, soaking up the gasoline until the pressure is released.

Now, have a helper hold down the white tab facing the front of the car with a large screwdriver so the fuel pump does not turn. Use another large flat screwdriver and a rubber mallet to unscrew the metal ring holding the fuel pump in the tank. Hit it counterclockwise. Once the metal ring is loose, remove it. Then, lift the top of the fuel pump off and place it to the side, still connected.

Reach into the tank and pull up on the fuel sender and unplug it from the fuel pump. There are two tabs on either side of it that you just squeeze and pull upward. Replace with the new fuel sender (sensor). It has a slot that it snaps down into that only goes in one direction. Pay attention to what it looked like before you removed it.

Finally, complete the reassembly in reverse. This entire process should take about 45 minutes. Be very careful and make sure there are no open flames or cigarettes around as you are working with gasoline.

Frequently asked questions