The inline fuel filter: How it works

The inline fuel filter is responsible for the purification of the fuel in a car. The fuel that goes into your car is not 100% clean. The fuel you buy from the gas station is most often contaminated with several particles and dirt that make it harmful to your car's engine. So, if the fuel that goes into your car is not 100% clean, what purifies it to make it less harmful to your engine?

Without the fuel filter, the fuel injector will be clogged and unable to inject fuel into the combustion compartment. The combustion engine needs fuel to perform, and fuel ordinarily contains organic and inorganic substances.

Inline fuel filter function

The inline fuel filter is sometimes ignored, but understanding its works, checking it, etc., is penultimate. In this article, you will learn all about:

  1. What the fuel inline filter is.
  2. Where the inline fuel filter sits.
  3. The function of the fuel filter.
  4. How to change an inline fuel filter.
  5. Symptoms of having air in the fuel filter.

What is an inline fuel filter?

inline fuel filter

Inline fuel filter[/caption]The fuel filter is a device that is positioned in a fuel system unit to eliminate dirt. It is usually made out of a metal or plastic can that has a filtration system to it. When it becomes faulty, it shows some symptoms. Check out our article on the symptoms of a bad fuel filter.

The earliest types of fuel filters were of plastic origin. The design was to fit the engines of vintage cars. Today, the fuel filter has taken a different design method, having filters that can now withstand the fuel system's high pressure while still doing its work as a purifying object.

Modern fuel filters are now made stronger than fuel filters that existed in older models of cars. The external covering of the filter has a harder covering, and the filtration system is locked properly to secure it against high pressure in the fuel system.

This way, the fuel filter always does its job when the car is in motion regardless of its speed. The inline fuel filter is the filter that is mounted outside of the fuel tank on the fuel line, and they are stronger because they are working inside and outside of the fuel unit.

The fuel filter acts as an engine protector, protecting the engine by purifying the fuel that powers the engine. If there is no fuel, the car engine won't work, and the fuel has to be as clean as possible.

Where is the inline fuel filter located in the car engine?

location of inline fuel filter

Location of inline fuel filter[/caption]The fuel filters are in between the fuel pump and the engine. In modern cars, the fuel filters are in the fuel tank, with some other necessary fuel units surrounding them.In much older cars, the fuel filters are under the body, connecting to the fuel line.

The fuel filter location in a car is largely dependent on factors like the car model, the year of manufacture, its type of fuel system, and some secondary features. Once you locate the fuel line in older cars, you can trace the fuel filter to the end of the line. However, this isn't the case in older models of vehicles though. The inline fuel filter, a type of fuel filter, is found outside of the fuel tank just right above the fuel line.

What are the functions of the fuel inline filter?

Function of inline fuel filter

The function of the inline fuel filter[/caption]From its definition above, the fuel filter's primary function is to remove substances in the fuel that powers a car's engine. How do substances get into the fuel? These substances get into the fuel during transportation of the fuel to its location, storage, or when filling the car's tank.Also, the fuel tank can have rust particles in its body, bacterial growths, and other dirt, polluting the fuel.

Consider the fuel as the water that goes into your body. If you would not drink dirty water or contaminated water, a complex machine like a car avoids taking a contaminated liquid into its main compartment. Condensation in the fuel tank that forms water can also be harmful to the car's fuel, especially when the car runs on diesel.The presence of substances in the fuel is harmful to the fuel unit because of their nature.

When the dirt becomes too much, it directly affects the fuel injection, which sends fuel to the combustion, and the injection gets clogged. In diesel engines, water causes friction because it is the diesel that serves as a lubricant to all the engine parts. If water mixes with the diesel, the diesel loses its lubrication power, and the engine in turn overheats.

Therefore, in automotive fuel, water acts as a corrosion agent and can lead to the wearing out of the engine parts. In automotive fuels, water also causes clogging, increases in smoke emissions, affects the engine's performance because the fuel will not burn as it ought to. So the engine will reduce in performance.

How to change an inline fuel filter

dirty fuel filter

Whenever you notice that your fuel filter is showing symptoms of being bad, you can change it yourself by following the steps below. To change a fuel filter, you need the following:

  1. A new fuel filter
  2. A rag
  3. A bowl to contain the spilled fuel
  4. Open-end wrenches
  5. Screwdrivers
  6. a jack
  7. Jack stands
  8. Goggles
  9. Gloves
  10. Protective gear, and
  11. A piece of old cloth.

Steps to change it

First, you need a well-ventilated area and keep highly flammable items away.

  1. Locate the fuse box and remove the fuse. Then, the fuse removal will remove the power supply to the fuel pump and relieve the pressure built in the fuel lines. If you cannot find the fuse box, please check your car's manual for guidance.
  2. Ensure the vehicle is not in motion or moving. The car should be in its park mode or should be neutral to prevent it from moving mistakenly.
  3. Run the car's engine for a few minutes to help release pressure from the fuel lines.
  4. Switch off the engine finally and re-insert the fuse.
  5. Disconnect the negative terminal of the car's battery. To prevent the engine from starting by any fault while you are still working on the vehicle. Carefully clamp the negative terminal.
  6. Locate the fuel filter in your vehicle, depending on where it is located.
  7. Attach a container under the filter to catch any fuel that will pour out the fuel filter. Furthermore,  remove the plastic clips that hold the filter using a screwdriver.
  8. Disconnect the fuel lines from the fuel filter.
  9. After removing the fuel lines, you carefully remove the fuel filter by sliding it from its place. If no screws are securing it, remove it easily. But if there are screws, unfasten the screws carefully while removing the filter.
  10. Check the new filter specifications if it fits the old one in size and outlook.
  11. Place the new fuel filter where the old one was and then replace the fuel lines. Replace the screws holding the filter.
  12. Reconnect the negative terminal, turn your engine on and run it for a few minutes.

Symptoms of having air in an inline filter

symptoms of air in fuel inline filter

An inline fuel filter[/caption]The symptoms of having air in the fuel inline filter are dangerous to a car. Some of the symptoms are:

  • Engine misfires
  • Decreasing engine power
  • Carburetor flooding
  • Engine stalling
  • Fuel leaks
  • Problems when starting the car.

Steps to fix an inline filter

To fix the air in the fuel filter that may have gotten there during a filter change, follow the steps listed below:

  1. Turn off the fuel valve
  2. Clean the fuel filter compartment
  3. After installing a new filter by following the steps above
  4. Fill the car with new fuel and get rid of the old fuel in the car also in the fuel filter
  5. Open the bleed plug close to the fuel tank
  6. Open the fuel supply valve to get fuel to the fuel filter and fuel pump
  7. Allow the fuel to get to the pump to replace the trapped air. Furthermore, pump several times so that the air leaves from the bleed plug holes.
  8. Also, bleed the fuel lines and fuel injectors.
  9. Then, close the bleed plus after all the air has been removed.
  10. Finally, start the engine again until it does not exhibit any of the symptoms again.

Key Takeaway

  • No matter how minute they might look, the inline fuel filters contribute majorly to the engine's effective running.
  • Therefore, it is important to know what it is and how it works, as explained above in this article.
  • Furthermore, there are other units with a fuel unit that are as important as the filter. You should attend to any change in the car engine right away.

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