Smart Car Maintenance: Replacing Fuel Filter

Changing the fuel filter on a smart car is a relatively simple process that can be done at home with the right tools. The fuel filter is located either along the fuel line on the bottom of the car, just past the fuel pump, or in the engine bay on the line that leads to the fuel rail.

Before beginning, it is important to relieve the pressure in the fuel system by removing the fuel pump fuse or relay and allowing the engine to run until it stalls. This will prevent fuel from spraying out when the filter is removed. It is also important to disconnect the battery and raise the vehicle using a jack to access the fuel filter.

Once the fuel system is depressurized and the vehicle is raised, the fuel filter can be located and removed by disconnecting the fuel lines and sliding it out of its bracket. A new fuel filter can then be installed by sliding it into the bracket and reconnecting the fuel lines.

It is important to note that some smart car models may have the fuel filter integrated into the fuel pump, in which case it is recommended to hire a trained technician to replace the filter. Additionally, the fuel filter should be replaced at the manufacturer's recommended interval to ensure optimal fuel system performance.

Relieve the pressure in the fuel system

To relieve the pressure in the fuel system of your smart car, you will need to run the vehicle without the fuel pump functioning for a short time. This can be done by removing the fuel pump fuse.

Locating the Fuel Pump Fuse

The first step is to locate your vehicle's fuse box. Most vehicles have a fuse box in the interior of the car as well as under the hood. Refer to your vehicle's owner's manual to locate the appropriate fuse box. If you do not have an owner's manual, try referring to the auto maker's website. The fuse for the fuel pump is often located in the fuse box inside the car.

Removing the Fuel Pump Fuse

Once you have located the correct fuse box, use the diagram provided on the fuse box cover or in the owner's manual to identify the fuse that powers the fuel pump. Use a pair of needle-nose pliers or plastic tweezers to remove the fuse. With the fuse removed, the fuel pump will not function when you start the engine.

Ensuring the Vehicle is Not in Gear

Although the engine will not receive a fresh supply of fuel from the gas tank, there will still be enough fuel in the lines for the engine to start and run briefly. Make sure automatic vehicles are in park and vehicles with a standard transmission are in neutral with the parking brake engaged. Although the vehicle will only run briefly, it will still move if left in gear.

Starting the Engine

Insert the key into the ignition and turn it to start the motor as you usually would. The engine should start easily as it expends the fuel remaining in the fuel system past the fuel pump. If the engine turns over but then sputters out, it may not have had sufficient pressure in the lines to force the fuel into the engine. If the engine dies, the fuel pressure will be sufficiently relieved.

Allowing the Engine to Run

Allow the engine to run for a minute or two before shutting it off. Depending on the fuel system in your vehicle and its average fuel consumption, the amount of time it will run without a functioning fuel pump can vary. It does not need to run until it dies. Without the fuel pump functioning, the pressure will be relieved in the fuel lines fairly quickly. Allowing the engine to run until it dies may make it difficult to start it again.

Re-inserting the Fuel Pump Fuse

With the pressure relieved from the fuel system and the engine off, you can re-insert the fuse that powers the fuel pump. Place the cover back on the fuse box and return any pieces of the trim you may have needed to remove to access it. Make sure the vehicle is off before replacing the fuse you removed. Do not start the engine again after inserting the fuel pump fuse.

Disconnect the battery

Disconnecting the battery is an important step when changing the fuel filter on your smart car. This is because it ensures that the engine cannot be started accidentally while you work on the car.

To disconnect the battery, first, locate the negative terminal on the battery. You will need to use a hand or socket wrench to loosen the nut holding the cable onto the negative terminal. Be careful not to remove the nut completely. Once the nut is loose, disconnect the cable from the negative terminal. Tuck the negative cable to the side of the battery, ensuring that it does not touch the battery terminal.

It is important to note that you should only disconnect the negative cable and not the positive cable. This is because the negative cable is connected to the ground, and disconnecting it will prevent any electrical current from flowing through the car.

By disconnecting the battery, you can work on the fuel filter without worrying about accidentally starting the engine. This is important for your safety, as well as for preventing any potential damage to the car.

Once you have finished changing the fuel filter, you can reconnect the battery by simply reversing the steps. Make sure that the negative cable is securely connected to the battery terminal, and that the nut is tightened before starting the engine.

Locate the fuel filter

To locate the fuel filter of your smart car, refer to your vehicle's service manual. The fuel filter is usually located in one of two places. The most common location for modern vehicles is along the fuel line on the bottom of the car, just past the fuel pump. In some vehicles, the fuel filter is located in the engine bay on the line that leads to the fuel rail.

If you are having trouble locating the fuel filter, it may be helpful to know that the fuel filter is positioned between a car's fuel pump and the fuel injectors. It is designed to filter out rust, scale, dirt and impurities from the fuel.

For the Smart Fortwo 450, the fuel filter is located on the off-side, in front of the rear wheel arch. You may want to remove the wheel for more access.

Remove the old fuel filter

To remove the old fuel filter from your Smart Car, you will first need to relieve the pressure in the fuel system. This can be done by locating and removing the fuel pump fuse, ensuring the vehicle is not in gear, and starting the engine for a minute or two until it runs out of fuel. Once the pressure is relieved, re-insert the fuel pump fuse and disconnect the battery.

Now, locate the fuel filter. In most modern vehicles, this is found along the fuel line on the bottom of the car, just past the fuel pump. However, in some vehicles, the fuel filter is located in the engine bay on the line that leads to the fuel rail. You may need to refer to your vehicle's service manual to determine the exact location. If the fuel filter is located on the underside of your vehicle, you will need to jack up the car to access it.

Place a bowl or bucket beneath the fuel filter to catch any fuel that may spill out when disconnected. The fuel filter is usually held in place by two plastic clips. Use a flat-head screwdriver to pop them out of the holes. These clips may break as you remove them, so purchasing replacement clips along with your new fuel filter is advised.

With the clips removed, slide the fuel lines away from the filter and towards the bowl or bucket to catch any spilled fuel. Wear eye protection and gloves during this step to protect yourself from fuel splatter. Now, simply slide the fuel filter out of its bracket. The filter will have a slight bell shape, allowing it to slide out in only one direction. If your filter sits differently in the bracket, you may need to slide it towards the back of the car to remove it.

Install a new fuel filter

Now that the old fuel filter has been removed, it's time to install a new one.

First, compare the new filter to the old one. Check that they appear to be the same outside diameter, that the nozzles are the same size, and that it will fit into the bracket. If the fuel filters do not match, you will need to return the new one for the correct replacement filter.

Next, slide the new fuel filter into the bracket. It should stop when it is seated properly. Be careful not to damage the housing of the fuel filter, as that may cause a leak. If you find yourself pushing hard on the filter to make it fit, it is likely not the correct one.

Now, fasten the fuel filter to the fuel line. Slide the fuel lines onto the front and back of the filter the same way they were attached to the old one. With the fuel line in place on the filter, slide the plastic clips through the holes on the fuel line nozzle to secure the line in place on the fuel filter. If the plastic clip breaks as you slide it in, do not attempt to drive the vehicle until you replace the broken clip.

Finally, lower the vehicle off of the jack stands. Jack up the car to relieve the weight on the jack stands, then slide them out from beneath the vehicle. Once the jack stands are clear, lower the vehicle to the ground. Reconnect the battery to complete the installation.

Frequently asked questions