6 Bad Fuel Rail Pressure Sensor Symptoms and Replacement Cost

For most car owners, fuel economy is a top priority. When your car struggles to get the miles per gallon you hoped for, it is easy to chalk it up to some unlucky circumstance. But when your vehicle’s fuel economy starts to decline despite regular oil changes and inspections, you may have a problem with your fuel rail pressure sensor.

A fuel rail pressure sensor is a vital component of your vehicle’s engine that monitors the pressure of the fuel in the engine. When the pressure is too low, it can cause issues such as missed or poor fuel economy, stalling, and even a potential engine fire. A defective fuel rail pressure sensor can also cause the car to experience a “knocking” noise when it is started. Read on to learn more about these symptoms and cost to replace the sensor.

Symptoms of a Bad Fuel Rail Pressure

A new fuel rail pressure sensor

Symptoms of a bad fuel rail pressure sensor can vary depending on the model and year of your vehicle, but the following symptoms are common for all vehicles:

Knocking Noise

Many drivers notice knocking noises in their engine when they start their car. These noises are typically caused by the pistons hitting one another as they start up. If the fuel rail pressure sensor fails, an excessive amount of fuel may be pumped into the cylinders. This can cause the engine to run rough and create knocking noises, and in most cases, a defective fuel rail pressure sensor will be the cause.

Increased exhaust smoke from your engine

Your vehicle’s exhaust system is responsible for removing harmful gasses such as carbon monoxide from your engine. A defective fuel rail pressure sensor allows insufficient fuel to access the combustion chambers, resulting in incomplete combustion and extra unburned oxygen in your vehicle’s exhaust.

Exhaust smoke from vehicle by Mike Roberts / CC BY-SA 2.0

This increases the amount of harmful gasses exiting your engine, which can cause an increase in exhaust smoke.

If you notice that your vehicle is producing excessive smoke when you drive it, it could be a sign of a problem with the fuel rail pressure sensor. In most cases, a fuel rail pressure sensor replacement will resolve the issue.

Stalling Engine or Trouble Starting your Car

If your fuel rail pressure sensor fails, the engine may struggle to start due to problems with the fuel pump providing fuel to the injectors.

Your vehicle may experience difficulty starting if it uses an excessive amount of fuel or if it experiences a lack of proper ignition. This can be caused by a faulty fuel rail pressure sensor. In many cases, a repair to the fuel rail pressure sensor will resolve the issue.

Engine light on in your dashboard

Check engine light by Stephen Mellentine / CC BY-NC-ND 2.0

The check engine light on your dashboard has two primary purposes; to tell you that there is a problem with your vehicle, and to let you know which system is the problem. In the case of a defunct fuel rail pressure sensor, the light may indicate a fault code for “P0106.” This code is typically associated with a bad fuel rail pressure sensor.

Reduced gas mileage

A faulty fuel rail pressure sensor can cause your engine to use more fuel than it usually would. This can cause a reduction in your car’s gas mileage, and may also result in decreased performance. If you think your fuel economy has decreased since the last time you filled up your vehicle, you should check the fuel pump and fuel rail pressure sensors. If either of these is defective, a replacement may be necessary.

Poor acceleration

Most cars experience poor acceleration when they are low on gas. This is typically due to a lack of fuel being delivered to the engine. If the fuel rail pressure sensor in your car malfunctions, it can cause excessive pressure to build in the system. This will make it harder for your engine to accelerate and could cause you to have to put more effort into accelerating than you would typically need to do. If you have poor acceleration, when your car is only partially full of fuel, the fuel rail pressure sensor may be malfunctioning.

Causes of a Bad Fuel Rail Pressure Sensor

Many things can lead to a malfunctioning fuel rail pressure sensor, including:

A malfunction in the fuel system

Malfunctions such as a bad fuel pump or an ill-fitting fuel injector can cause your fuel rail pressure sensor to go bad.

Fuel pumps by ND-Photo.nl / CC BY-NC-ND 2.0

If your fuel pump is having trouble pumping fuel into your engine, it will lead to a buildup of excess pressure in your system. This pressure can cause a malfunctioning fuel rail pressure sensor.

Damaged Wires

Damage to the wires connecting your fuel rail pressure sensor can also cause it to fail.

Damaged wires can occur if your spark plugs become loose over time or if you accidentally strike them with your foot when changing a tire on your vehicle.

Corrosion

A bad fuel rail pressure sensor can also be the result of corrosion on the inside of your fuel rail pressure sensor. Fuel rail pressure sensors are commonly located beneath the vehicle and can become corroded or damaged from exposure to external factors like oil leaking into your fuel system from your oil pan or debris building up in your gas tank. If this occurs, it can lead to premature failure of your fuel rail pressure sensor and other components of the fuel system.

Debris

A bad fuel rail pressure sensor can also be the result of damage that is sustained during vehicle use. For example, a fuel rail pressure sensor can be damaged by water or debris that gets stuck in the system. Furthermore, due to the presence of dirt impurities

Clogged fuel injectors by Greg Myers / CC BY-NC-ND 2.0

in low-quality fuel, refilling your fuel filter with them may cause your fuel injectors to become clogged and your fuel rail pressure sensor to malfunction.

Wear and Tear

A defective fuel rail pressure sensor can also be the result of wear and tear. Over time, the sensor can become damaged and lose its ability to accurately measure fuel rail pressure. This can lead to problems with the engine’s ability to properly deliver fuel to

the cylinders.

How does a Fuel Rail Pressure Sensor Work?

A fuel rail pressure sensor is responsible for measuring the pressure of the fuel in the fuel line. This information is fed back to the electronic control unit (ECU) of the vehicle.

The ECU of a vehicle by Ernesto Andrade / CC BY-ND 2.0 

The ECU controls the amount of fuel that is sent to each fuel injector so that the right amount of fuel is sent to the engine so that it can operate at peak performance. If the fuel rail pressure sensor becomes damaged, the ECU may not be able to accurately measure the fuel pressure. This can lead to several problems with the engine, including poor fuel economy and reduced performance.

Fuel Rail Pressure Sensor Replacement Cost

The cost of replacing a fuel rail pressure sensor varies based on the type of vehicle you drive and the make and model of the specific sensor required for your vehicle. However, in most cases, a replacement will cost between $200 and $340, labor inclusive.

However, this number can change dramatically if the vehicle is under warranty or if the dealer has discounts on parts needed to carry out the repair. If your car is still under warranty, the dealer will usually pay for a fuel rail pressure sensor repair if the problem was caused by manufacturing faults.

If you are not able to get the repair done by a dealer, or if you would like to carry out the repair yourself, the cost of a replacement fuel rail pressure sensor will be between $60 and $100. In some instances, you may be able to find the exact part needed online at a much lower price than if you were to purchase it directly from the dealer. However, make sure that you can get the correct part for your vehicle and that it is compatible with your make and model.

Can I do the repair myself?

In most circumstances, if you have a general understanding of automotive systems and the necessary tools, you should be able to conduct the repairs yourself. Hiring a mechanic, on the other hand, may be a more cost-effective choice if you are unfamiliar with automotive maintenance or lack the essential tools.

Factors that influence the cost of a fuel rail pressure sensor replacement

The two main factors that influence replacement cost of a fuel rail pressure sensor include:

Make and Model of the vehicle

This will influence the cost of a fuel rail pressure sensor replacement because the price of the part is dictated by the amount of research that manufacturers have to do to design and create the part for each vehicle model. Different models have different systems also, so the sensor may not be compatible with all of the systems of that model.

Condition of the vehicle

If the vehicle has been in a lot of accidents, there may be more damage to the fuel rail pressure sensor that will need to be repaired. In addition, if the vehicle has been sitting for a long time without being used, the fuel rail pressure may be low, which may require the sensor to be replaced.

FAQs

1. What size fuel injectors will I need for my vehicle?
2. This is dependent on the make and model of your vehicle. However, most cars require injectors that are 0.060 inches in diameter. If you need to replace the fuel rail pressure sensor, your injectors will likely need to be replaced too. This will help to ensure that all of the components of the fuel system are in proper working order.

1. Why do I need to replace my fuel rail pressure sensor?
2. The sensors can become damaged due to a variety of reasons, such as sediment build-up in the sensor’s filter or the sensor itself becoming corroded from contaminants in the vehicle’s fuel. You must have the fuel rail pressure sensor replaced right away if you notice any signs that it is failing or there is an issue with the fuel rail pressure sensor, as it can cause damage to your engine if it is not repaired.

1. How long does the fuel rail pressure sensor usually last?
2. The lifespan of a fuel rail pressure sensor is typically around 10 years. However, if the sensor is not changed or fixed as needed, it may fail in the future. On average, the fuel rail pressure sensor has a typical lifespan of 5-7 years.

Conclusion

If you are having problems with your vehicle’s fuel system, you should have the fuel rail pressure sensor changed as soon as possible. By understanding what the symptoms of a faulty fuel rail pressure sensor are, you can better determine if it is time to have the

sensor replaced. You may also purchase a fuel pressure regulator to prevent fluctuations and help keep your fuel pressure constant.

Additionally, understanding the functions of your fuel rail pressure sensor can help you avoid issues in the future that may lead to damage to the engine if left unaddressed. If you have any questions regarding how to replace your fuel rail pressure sensor or notice any symptoms that it may need to be replaced soon, please contact a professional.