What Is a Fuel Lift Pump? How It Works and When It Fails

Have you ever thought about why your diesel engine sometimes fails to start suddenly, or why it feels like you are stepping on cotton when you step on the accelerator? The problem may be a small component that you usually don’t pay attention to at all - the fuel lift pump!

Today's article will help you understand the following three key questions:

How does a fuel lift pump work?

What type of pump is the fuel lift pump?

Symptoms of a bad fuel lift pump

Don’t worry, keep reading, and you will understand the engine's "call for help"!

 

How Does a Fuel Lift Pump Work?

The main function of the fuel lift pump is to "lift" the fuel in the fuel tank and deliver it to the engine's injection pump. In diesel engines, it is especially important because diesel needs to be injected at high pressure to burn.

 

Simply put, the fuel lift pump is like a "transporter". It continuously delivers the fuel in the fuel tank to the front end of the engine to ensure that the engine has enough fuel to burn and operate.

 

When you turn on the ignition switch, the fuel lift pump will be started. In this way, the fuel lift pump starts to absorb the fuel in the fuel tank, passes through the fuel filter, and finally delivers it to the injection system, forming a complete fuel cycle.

 

What Type of Pump Is the Fuel Lift Pump?

Fuel lift pumps can generally be divided into the following types:

Mechanical Fuel Lift Pumps

This type of fuel lift pump is common in old diesel engines. It is driven by a camshaft and relies on mechanical movement to suck and deliver fuel. In addition, the volume and fuel pressure of this type of fuel lift pump are also fixed.

 

Electric Fuel Lift Pumps

Modern engines use more of this type, which is driven by an electric motor, flexible to install, and more stable to work. This type of lift pump is common in electronic control systems. The volume and fuel pressure of this fuel lift pump are adjustable.

 

Gear Pumps

Gear pumps are usually used in heavy machinery or high-power diesel engines, and can provide greater fuel flow and pressure. When choosing to replace a fuel lift pump, be sure to match the equipment model and engine type.

 

Symptoms of a Bad Fuel Lift Pump

Once the lift pump fails, it will affect the fuel supply of the entire fuel system. Common symptoms are as follows:

 

1. Difficulty in starting the engine

If the starting time is significantly extended or multiple ignitions are required, it is likely that the fuel delivery is poor.

 

2. Engine stalling or unstable idling

Heavy equipment suddenly stalls, shakes, and other problems during driving. This indicates that the fuel supply is intermittent, and the pump pressure may be insufficient.

 

3. Power reduction

When stepping on the accelerator, it feels sluggish and the heavy equipment output power is insufficient. This phenomenon is insufficient fuel flow.

 

4. Abnormal noise or oil leakage from the oil pump

An abnormal buzzing sound is emitted during operation or there are signs of oil leakage on the outer shell. This indicates that the pump body has been worn or the seal has been damaged.

 

Once the above symptoms occur, it is recommended to check and replace the lift pump in time to avoid greater repair costs.

 

Although the fuel feed pump is small, it plays a big role in the operation of the equipment. Understanding its working principle, types and failure symptoms can help you extend the life of the engine and avoid high repair costs caused by poor fuel supply. When purchasing a quality lift pump, don't forget to check out MyMROmarts!

 

If you are looking for a reliable aftermarket fuel feed pump, it is recommended to visit MyMROmarts. The customer service team is professional and can help customers choose the right model to avoid buying the wrong parts.