How They Work

An in-tank mounted electric fuel pump is a type of fuel pump that is located inside the fuel tank of a vehicle. The primary function of the fuel pump is to deliver fuel from the tank to the engine, where it is burned to produce power.

An electric fuel pump assembly typically consists of several components that work together to deliver fuel from the tank to the engine. These components include:

Fuel pump motor: The electric motor is the heart of the fuel pump assembly. It is responsible for driving the impeller and creating the pressure needed to deliver fuel to the engine.

Impeller: The impeller is a small propeller-like device that is connected to the motor. As the motor spins, the impeller creates a low-pressure area that draws fuel into the pump and a high-pressure area that pushes fuel out of the pump and into the fuel lines.

Fuel filter: The fuel filter is located on the inlet side of the pump and helps to remove any debris or contaminants that may be present in the fuel.

Fuel pressure regulator: The fuel pressure regulator is located on the outlet side of the pump and is responsible for maintaining a consistent fuel pressure. It achieves this by regulating the amount of fuel that is returned to the fuel tank.

Check valve: The check valve is a one-way valve that is located on the outlet side of the pump. It helps to prevent fuel from flowing back into the fuel tank when the pump is not running.

Sending unit: The sending unit is a sensor that is located in the fuel tank and is responsible for measuring the fuel level. It sends this information to the fuel gauge on the dashboard.

Wiring harness: The wiring harness connects the fuel pump assembly to the vehicle's electrical system. It provides power to the fuel pump motor and allows the fuel level sensor to communicate with the fuel gauge.

Together, these components work to ensure that fuel is delivered to the engine at a consistent pressure and flow rate, ensuring optimal engine performance and fuel efficiency.

One of the key advantages of an in-tank mounted electric fuel pump is that it is able to provide a consistent flow of fuel to the engine, even when the fuel level in the tank is low.

Another advantage of an in-tank mounted electric fuel pump is that it is able to operate quietly and efficiently. Because the pump is located inside the tank, it is insulated from the surrounding environment, which helps to reduce noise and vibration. Additionally, the electric motor is able to deliver fuel at a constant rate, which helps to improve fuel efficiency and reduce emissions.

Why They Fail

Electric fuel pumps can fail for a variety of reasons. Here are some of the most common causes of electric fuel pump failure:

1. Overheating: Perhaps the most common cause of premature electric fuel pump failure is overheating. If the fuel pump is running for an extended period of time, it can overheat and cause damage to the pump motor or other components. This is especially common in vehicles that are driven in hot climates or in heavy traffic fuel.
2. Contaminants: Dirt, debris, and other contaminants can get into the fuel tank and clog the fuel filter or damage the fuel pump. Over time, this can cause the fuel pump to wear out or fail prematurely.
3. Low fuel level: If the fuel level in the tank is consistently low, it can cause the fuel pump to work harder than it needs to. This can cause the pump motor to overheat and fail. It also causes the sediment to get sucked up. This will be explained in more detail later in the article.
4. Age: Like all mechanical components, electric fuel pumps will eventually wear out over time. As the pump ages, it may become less efficient, produce lower fuel pressure, or simply stop working altogether.
5. Electrical issues: One of the most common reasons for electric fuel pump failure is an electrical problem. This could include issues with the fuel pump relay, wiring, or the fuel pump itself. If the electrical connections are loose, corroded, or damaged, it can cause the fuel pump to malfunction or stop working altogether.

To prevent electric fuel pump failure, it is important to follow the manufacturer's recommendations for maintenance and repair. This may include regular fuel filter replacements, checking for loose or corroded electrical connections, and monitoring fuel pressure levels.

Signs That Your Electric Fuel Pump May Need Replacing

Here are some common signs that your fuel pump may need to be replaced:

Engine sputtering or stalling: If your engine is sputtering or stalling while you're driving, it could be a sign that your fuel pump is failing. This is because the fuel pump is not providing enough fuel to the engine to keep it running smoothly.

Loss of power: A failing fuel pump can cause a loss of power or acceleration, especially when you're trying to accelerate quickly or climb a hill.

Whining noise: If you hear a high-pitched whining noise coming from the fuel tank, it could be a sign that your fuel pump is failing. This noise is caused by the electric motor inside the fuel pump, which may be struggling to keep up with the demand for fuel.

Hard starting: If your engine is hard to start, it could be a sign that the fuel pump is not providing enough fuel to the engine. This is especially true if the engine cranks for a long time before starting.

Check engine light: If your check engine light comes on, it could be a sign that your fuel pump is failing. This is because the fuel pump is an important component of the engine management system, and a failure can trigger the check engine light.

If you experience any of these symptoms, it's important to have your vehicle inspected by a qualified mechanic as soon as possible. Delaying repairs could lead to further damage and potentially costly repairs.

Tips To Avoid Premature Fuel Pump Failure 

There are several steps you can take to help prevent premature fuel pump failure:

Don't let your fuel level get too low:  Driving on less than a quarter tank of fuel can be detrimental to your vehicle's fuel system, especially the electric fuel pump. This is because the fuel pump relies on the surrounding fuel to act as a lubricant and coolant, which helps to regulate the pump's temperature and prevent it from overheating.

When there is less fuel in the tank, the pump has to work harder to draw fuel from the bottom of the tank, which causes it to spin faster and generate more heat. (The more fuel in a tank, the more gravity assists and the less work the pump has to do). Without the surrounding fuel to act as a coolant, this increased heat can cause the pump to overheat, leading to premature wear and failure.

In addition to the lack of coolant, driving on a low fuel level can also increase the risk of sediment and debris entering the fuel pump. This is because sediment and debris tend to settle at the bottom of the fuel tank, and driving with a low fuel level can cause these particles to be stirred up and sucked into the fuel pump.

To prevent these issues, it is generally recommended to keep your fuel tank at least a quarter full at all times.This helps to ensure that the fuel pump is always surrounded by an adequate supply of fuel, which helps to regulate its temperature and prevent sediment from entering the fuel system. Additionally, keeping your fuel tank at a higher level can also help to prolong the life of your fuel pump and reduce the risk of costly repairs down the road.

Use high-quality fuel: Using high-quality fuel can help prevent premature fuel pump failure by reducing the risk of contaminants and debris getting into the fuel system. It's important to use fuel that meets the manufacturer's specifications for your vehicle.

Replace your fuel filter regularly: A clogged fuel filter can put extra strain on your fuel pump and cause it to fail prematurely. It's important to replace your fuel filter according to the manufacturer's recommendations.

Check for leaks: Fuel leaks can damage your fuel pump and other components of the fuel system. It's important to regularly check for leaks and have them repaired promptly.

Don't ignore warning signs: If you notice any of the warning signs of fuel pump failure, such as engine sputtering, loss of power, or a whining noise from the fuel tank, it's important to have your vehicle inspected by a qualified mechanic as soon as possible.

By following these steps, you can help prevent premature fuel pump failure and keep your vehicle running smoothly.

How we can help

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