One of the most essential parts of your vehicle’s fuel delivery system, the fuel pressure regulator is responsible for how much fuel the engine receives at any point in time. When the regulator fails, it can create significant engine performance issues and may even prevent you from safely driving your car.
There are several symptoms associated with a bad fuel pressure regulator that you may be noticing affecting your car. To help you properly evaluate whether or not a faulty fuel pressure regulator issue is the culprit, we have listed the most notable symptoms for you to read through.
If your vehicle is experiencing one or more of these symptoms, you should consult with a professional to get repair recommendations.
What Is a Fuel Pressure Regulator and Why Is It Important?
As we touched on briefly above, the fuel pressure regulator is part of your car’s fuel delivery system. Once you start your car, the fuel pump will remove a specific amount of gas from your car’s tank. Then, it will be passed through a filter and move down the fuel line to the injectors. After it reaches the injectors, it moves into the combustion chamber and ignites, powering your vehicle.
The fuel pressure regulator works to ensure that the amount and pressure of the fuel sent from the pump to the combustion chambers stays at a level amount (cars need a precise mix of air and fuel to stay running properly). If the regulator detects that the fuel pressure is too high, the gas flow will be stopped and excess returned to the tank.
When your fuel pressure regulator is faulty, it may allow too much fuel into the combustion chambers or too little, which can cause serious issues when it comes to driving your car smoothly. It may also prevent your car from starting altogether or cause issues with accelerating, problems that have the potential to become very dangerous.
Symptoms of a Bad Fuel Pressure Regulator
The below symptoms are important to understand so that you can evaluate whether or not a bad fuel pressure regulator is the culprit behind your car’s problems.
Black Smoke From the Exhaust
One of the more noticeable symptoms of a bad fuel pressure regulator, black exhaust smoke occurs when your engine is receiving too much fuel. Any excess gas that isn’t needed will be burnt up and sent out the exhaust, causing a thick cloud of black smoke.
It is important to get this symptom checked out as soon as possible, as there are other vehicle issues besides a bad fuel regulator that can cause black exhaust smoke.
Engine Won’t Start
If your car’s engine simply won’t start, there is a good chance that there isn’t enough fuel reaching the combustion chamber. Too little fuel will prevent your car from starting altogether and can be a sign of a faulty fuel pressure regulator.
However, much like with black exhaust smoke, several other vehicle issues can prevent your car from starting properly, so you should get this problem checked out by a professional as soon as possible to stay on the safe side.
Engine misfires will typically feel like a vibrating sensation when your car is idle. You may also experience rough acceleration or loud sounds coming from the engine while driving or remaining idle. These misfires are caused by an incorrect amount of fuel being delivered to your engine at any one time.
If you are experiencing this symptom, you should look to get it fixed as soon as possible, because engine misfires can severely damage the engine over time and may make for a more costly repair.
Poor Fuel Efficiency
A decrease in fuel efficiency is a major sign that your fuel pressure regulator is not working. When the regulator allows too much gas into the combustion chamber, you will be burning up the excess gas instead of having it returned to the gas tank. This causes you to go through gas faster than you normally would have.
Alternatively, if your engine doesn’t have enough gas reaching the combustion chambers, it may be working harder and will try to draw more fuel to compensate. This action will also cause poor fuel efficiency.
Issues Accelerating or Decelerating
Because the fuel pressure regulator sends fuel to the combustion chamber whenever you need to accelerate, you may experience rough acceleration, lurching, slow acceleration, or slow deceleration as a result of a bad fuel pressure regulator.
This can cause significant safety issues because not having control of when your car accelerates or decelerates may lead to a serious accident. If you notice this symptom, you should visit a professional as soon as possible in order to avoid further problems.
Noises in the Fuel Pump
In most cases, you will not ever hear a sound coming from your fuel pump. However, if you have a bad fuel pressure regulator, you may be able to hear loud humming or whining noise as soon as you turn on your car or when you accelerate. This is due to the fuel pressure regulator not sending the right amounts of fuel toward the engine, causing issues in the fuel pump and creating noise.
Spark Plugs Appear Black
Spark plugs are necessary for the fuel delivery system to ignite fuel once it reaches to the engine. If you have too much fuel heading to the combustion chambers because of a bad fuel pressure regulator, carbon deposits will appear on the end of the spark plug when the mixture ignites.
Keep in mind that this symptom does not apply to diesel engines as they do not have spark plugs and instead rely on spontaneous combustion to ignite the fuel.
A fuel pressure regulator has seals on both sides; if these seals are broken, fuel may be able to pass through into the other areas of your car or leak out the bottom. This leak of fuel may also cause issues when your regulator tries to send the correct amount of fuel to your engine.
If you do notice a fuel leak coming from your vehicle, it is important to figure out the exact location it is coming from and consult with a professional to fix the issue before any serious damage occurs.
Fuel in the Vacuum Hose
Your vehicle’s vacuum hose is a flexible tube that attaches to one side of the fuel pressure regulator. If your fuel pressure regulator is faulty, then you may be able to find traces of fuel in or on the outside of the vacuum hose.
The only way to determine this is to disconnect the vacuum hose from the regulator and inspect it – you can ask a professional to do this if you are not comfortable with performing this check on your car.
How Long Should a Fuel Pressure Regulator Last?
In most cases, a fuel pressure regulator will last the lifetime of your car. However, if you have an older car or a significant number of miles on your vehicle and you notice one or more of these symptoms, you may have a problem with your fuel pressure regulator.
The only way to tell for certain is to take your car to a professional to get the situation evaluated based on the symptoms you are noticing.
How Do You Maintain a Fuel Pressure Regulator?
Fuel pressure regulators are not typically on the list of regular maintenance upkeep, but if you want to ensure your regulator stays in top shape for as long as possible, you should try and change your fuel filters every 2 years or so. This will keep things running cleanly and smoothly in your fuel delivery system.
What Are the Repair Costs for a Fuel Pressure Regulator?
If you have determined that your fuel pressure regulator is bad, you may be wondering how much a repair of this part will cost you. Fortunately, it is not one of the most expensive items to replace on a car, but it can be a little bit pricey depending on how much labor needs to be done.
A replacement fuel pressure regulator alone will likely run you anywhere between $50 and $300 (electronic fuel pressure regulators are more expensive) and the labor can run between $100 to $200 or more, depending on how difficult it is to repair or replace your fuel pressure regulator. Together you can expect to pay anywhere between $150 to $500 for a repair.
Keep in mind that local mechanics or shops may offer cheaper labor costs than if you were to visit a dealership to get your car fixed.
Can You Replace a Bad Fuel Pressure Regulator Yourself?
It is possible to replace a bad fuel pressure regulator yourself, but you will need to have at least some experience DIYing cars; it can be a more difficult task for a novice to car repair. If you are interested in trying to fix your fuel pressure regulator at home, you can check out this article for more advice and instructions.
Keep Your Car Moving Safely
The fuel pressure regulator is an essential part of your car’s fuel delivery system and integral in keep your car moving smoothly. If your fuel pressure regulator isn’t working, you may be experiencing a number of symptoms that range from inconvenient black exhaust smoke to more dangerous problems with acceleration and deceleration.
Make sure to check out our full list of symptoms and compare them to your car’s issues so you can evaluate the possibility of your fuel pressure regulator being faulty and quickly get on the road to fixing it.