What Is a Fuel Rail? | How does Fuel Rail Pressure Sensor work?

The fuel system is a major part of the engine. It consists of a fuel pump, fuel tank, fuel injector, and fuel rails. The fuel injection system has the responsibility to supply fuel properly to the engine. The fuel rail is a most important part of the fuel system. The main function of the fuel rail is to supply fuel throughout the system. This article mainly explains the fuel rail function and symptoms of a bad fuel rail pressure sensor.

What Is a Fuel Rail?

A fuel rail is a high-pressure fuel line that properly supplies fuel to the fuel injector in an IC engine.

It is a vital part of the fuel injection system and is essential for the stable fuel supply to the injector. The fuel rails need proper care and maintenance for the proper operation. If they clog, they can’t properly supply fuel to the fuel engine; due to that, your engine may damage or clog.

fuel rail

Fuel rails are most commonly used in the latest direct-injection petrol engines to attain maximum fuel efficiency and reduce emission rates.

The use of this technology is increasing day by day to improve engine performance and fuel economy.  

What is a Fuel rail Pressure Sensor?

The fuel rail pressure sensor is a part of the fuel injection system used to observe the fuel pressure in the fuel rails. It is also known as a fuel pressor sensor. It installs near the center of the fuel rail and is connected to the vehicle’s central computer (Engine Control Unit).

fuel rail pressure sensor
Fuel rail Pressure Sensor

Many diesel engines and some petrol engines use fuel rail pressure sensors (often referred to as fuel pressure sensors).

As the sensor measures the pressure of the fuel rails, it sends a signal to the engine control unit (ECU), which utilizes it to adjust the timing and fuel economy of the vehicle.

What is the function of a Fuel Pressure Sensor?

The main function of the fuel rail pressure sensor is to continuously measure the fuel pressure in the fuel rails. When the sensor measures the fuel pressure inside the rails, it sends this collected data to the ECU system.

As the ECU receives data, it analyzes the data and makes reasonable changes to the timing and amount of the fuel being injected. This sensor helps to improve the performance of the engine in the existing operating conditions.

The ECU device specifies the precise amount of the fuel according to the engine requirements. If your injector injects more fuel than requirement into the burner, it will result in poor fuel economy. In addition, the service life of emission-related components reduces, and additional carbon emissions expel into the environment.

All vehicle manufacturers try to manufacture the best environmentally-friendly vehicles, which is a demand of current environmental conditions. In this case, the fuel rail sensor plays a big role in maintaining the emission rate and fuel economy of your vehicle.

Read Also: Working of Fuel Pump

Symptoms of a Bad Fuel rail Pressure Sensor

A faulty or bad fuel rail sensor has the following major signs:

1) Check Engine Light

The “Check Engine” warning light on the vehicle dashboard starts to illuminate if the fuel rail pressure sensor fails. This light only illuminates when the ECU senses a problem with the vehicle that is disturbing the engine performance.

This does not necessarily mean that the engine itself has a problem, but it may also represent that something else in the vehicle has a problem that stops the vehicle from working properly.  

You may not know at first that it is a fuel rail pressure sensor, but you can usually identify the problem with a diagnostic scan tool.

P0194, P0193, P0192, P0191, and P0190 are the most commonly used DTC codes that indicate problems with the fuel rail sensor.

2) Difficulty Starting Engine

As your vehicle fuel sensor damages, the engine control unit will not deliver the proper amount of fuel to the engine. This makes starting the vehicle difficult. In such a situation, you must immediately contact the technician and ask him to fix the problem.

3) Weak Acceleration

As you press the speed accelerator pedal and your vehicle doesn’t run according to your requirements, this problem may occur due to a defective fuel pressure sensor.

In such a situation, the ECU system cannot send the signal to the fuel system properly because the information it receives from the sensor is inaccurate. In such conditions, your ECU (engine control unit) doesn’t know how to meet your engine’s fuel needs.

4) Engine Stalling

If your vehicle has a bad fuel rail pressure sensor, the engine may start to generate stalling issues. In such a situation, your engine may suddenly stop while driving. It can also remain in idle mode.

This problem will make your driving very hard and dangerous. Therefore, you must fix this problem as soon as possible.

5) Fuel Mileage

If the fuel pressure sensor is not working properly, fuel consumption and fuel economy will be significantly reduce.

In such condition, the ECU sends a very high or very low amount of fuel to the combustion chamber through the fuel rails. A faulty fuel rail sensor increases the fuel consumption or fails the engine.  

The large vehicles will generally observe a reduction in fuel economy. For example, the fuel economy of a Duramax engine will be influenced more than that of an engine like the Honda Civic.

What is replacement cost of the fuel pressure sensor?

Many factors (such as your living area, the type of vehicle, and the brand type) affect the replacement cost of the fuel rail pressure sensor. The average fuel rail pressure sensor replacement cost is from $190 to $350.

Plz, note that in this cost, the labor cost is from $135 to $245 while the cost of the parts is from $55 to $105.

Labor Costs$135 – $245
Parts Costs$55 – $105
Total Average Costs$190 – $350

FAQ Section

What is the function of the Fuel rail?

The main function of the fuel rail is to take fuel from the fuel tank and deliver it to the fuel injector, which injects fuel into the engine combustion chamber.

Where is the fuel rail pressure sensor located?

Fuel rail pressure sensor is usually installed near the center of the fuel rail and is connected to Engine Control Unit (ECU).

These sensors are most commonly used in some gasoline engines and many diesel engines.

What does a fuel rail pressure sensor do?

The fuel pressure sensor basically senses the fuel pressure inside the fuel lines. After measuring fuel pressure, it sends this data to the engine control unit, which uses the data to control the fuel pressure inside the fuel rails.

What are the signs of bad Fuel Pressure Sensor?

Following are the most common signs of a bad fuel pressure sensor:

  • Fuel Mileage
  • Engine Stalling
  • Check Engine Light
  • Weak Acceleration
  • Difficulty Starting Engine
Read Also
  1. Different types of Engines
  2. Types of IC Engines
  3. Types of Diesel Engines
  4. Working and types of Fuel System
  5. Working of Fuel Pump
  6. How to put water in your Car?

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