6 Fuel Pressure Sensor Symptoms (+ Solutions)

Most car drivers don’t even know what fuel pressure sensor symptoms are, let alone do they understand its importance.

The fact that most people don’t know about a failing fuel pressure sensor means that it won’t get immediate attention when needed.

If your car has begun to experience poor or sluggish acceleration or hard starting, it may be a symptom of a failing fuel pressure sensor. A failing fuel pressure sensor can also cause a vehicle to stall at idle speeds, especially when the gas pedal is depressed slightly.

This article explains various fuel pressure sensor symptoms, how to fix them, and answers any questions you might have regarding the fuel pressure sensor and its replacement.

1. Poor Gas Mileage

When you start noticing an increase in your car gas consumption, it is a possible sign of a damaged fuel pressure sensor.

The fuel pressure sensor regulates your car engine fuel consumption, and therefore when it is damaged, there will be excess fuel sent into the combustion chamber.

The engine won’t be able to burn all the fuel at once, it wasn’t designed that way, so the unused fuel remains after the engine’s combustion process, causing harm to your engine.

Therefore whenever you notice this fuel pressure sensor symptom, please don’t ignore it.

2. Sluggish Acceleration

The result of incomplete combustion in a car is sluggish acceleration. As a result, your vehicle will find it difficult to accelerate.

In addition, the engine’s combustion process will be jeopardized when the injecting of fuel is no longer correct.

In such a situation, you will find it difficult to accelerate your car; the more you press the gas pedal, the more it feels like it’s not accelerating, or it will not accelerate per the pressure applied, unlike its used.

It is a possible fuel pressure sensor symptom when you notice such. Your car’s engine can get an excess or low amount of fuel when you have a bad fuel pressure sensor, which generally reduces your car performance.

Try and fix your car when you notice such a problem.

3. Car Starting Problems

A certain amount of fuel is required to start your car, and when your vehicle does not get that amount of fuel, it won’t start. This problem could be a result of a faulty fuel pressure sensor.

Spark ignition engines have an ignition coil that provides voltage for spark plug ignition. At the end of the compression cycle in the combustion chamber, the air-fuel mixture is ignited by the spark plug.

For compression ignition engines, self-ignition takes place due to air-fuel mixture compression.

Regardless of either compression ignition engine or spark engine, without the correct amount of fuel, it won’t start.

Therefore the engine will need to receive the right fuel for easy and proper engine startup.

4. Stalling

When your car stalls, you may feel powerless; this stalling results from an insufficient fuel rail pressure sensor.

In such a case, the engine will stop turning in between cycles. For a four-stroke engine, the following process takes place

  1. Intake stroke
  2. Compression stroke
  3. Power stroke
  4. Exhaust stroke

A power stroke occurs for every cycle when the fuel level is optimal, but little or no power is produced if the fuel level falls below that level.

When you face such a problem on a highway, it can be very frustrating and infuriating because you will then power from the engine to run the car. This symptom is a possible sign of a bad or damaged fuel pressure sensor.

5. Check Engine Light

There are many reasons why your car check engine light will come on, and a bad fuel pressure sensor is one of them.

Your check engine light is your first sign for most car problems, just that lots of people tend to ignore it until it’s too late.

6. Unburnt Fuel in Exhaust

Your car piston receives more fuel when the fuel rail pressure sensor goes bad; when this happens, some of this fuel will not burn in the combustion chamber, and they are trapped in the exhaust system. This is a bad fuel pressure sensor symptom

Also Read: Bad Catalytic Converter Symptoms & How To Fix

What Does the Fuel Pressure Sensor Do?

fuel pressure sensor symptoms

A fuel pressure sensor is a device that monitors the fuel pressure in a car fuel rail. It takes information from the fuel rail and transfers that information in the form of data to the ECU(Engine control unit)

The computer in the ECU will analyze the data and make adjustments where necessary, such as fuel injection and quality of fuel injected. This will enhance engine performance and the entire working condition of the car.

The engine control unit is tasked with specifying the amount of fuel necessary for the engine. if more gas is injected into the engine’s combustion chamber due to a bad fuel pressure sensor, it could decrease your vehicle’s gas mileage.

Your car’s lifespan will also decrease, and emissions from your car will increase, releasing poisonous gases into the atmosphere.

It is clear from this that the fuel pressure sensor is essential to a car and must function properly.

How Does the Fuel Pressure Sensor Work?

A fuel pressure sensor works like any other sensor, and it is calibrated with a sensing element. This sensing element has a tiny dome-shaped diaphragm, and it gets elongated when pressurized fuel moves in it.

There’s a voltage-producing element calibrated on the mechanical sensing part; the elongation of the sensing element is proportional to the voltage generated by the component.

So to make the energy detectable, the energy is amplified in a similar ratio.

The car Electronic Control Unit (ECU) receives the signal generated by the fuel pressure sensor. That will help regulate and determine the quantity of fuel injected into the combustion chamber.

The engine performance is essential, and it’s a factor of the amount of fuel sent into the combustion chamber; excess or low amount of fuel can affect the entire performance of the engine.

There’s AIR-FUEL RATIO(AFR), a ratio of air and fuel in the combustion chamber; the AFR governs the rich or lean running of the engine.

There will be more air than fuel when the AFR is greater; this could also mean lean engine running. When the AFR is less than one, there’s more fuel than air which means the rich running of the engine.

The AFR is adjusted when the fuel rail pressure sensor sends a signal to the ECU, which comes in voltage. Engine AFR is positioned at 14.7:1. When the amount of fuel increases, performance tends to increase with it.

A faulty fuel pressure sensor can lead to poor or wrong signals, which will affect the AFR in the combustion chamber and cause poor acceleration or stall the engine.

fuel pressure sensor symptoms

What Happens if Your Fuel Pressure Gets Too High?

Fuel pressure has a significant effect on the performance and lifespan of your car.

The fuel pressure system is a critical and delicate system of your vehicle, supplying fuel to the combustion chamber for the smooth running of the car. You may now wonder how you can know that there’s high fuel pressure.

In general, car components operate at their ideal level of efficiency. However, damages and underperformance result from low or high extreme levels.

When your fuel pressure is too high, it could be that the back soot coming from your exhaust has affected the engine. This can decrease fuel economy in the car.

Also, when the fuel pressure is low, the vehicle could face difficulty in starting due to a lack of fuel.

Can I Drive With a Bad Fuel Pressure Sensor?

If the fuel pressure sensor symptoms are not severe, you can still drive. You can still drive your car to a mechanic with ease when the car fuel pressure sensor starts to fail, but the problem will worsen if you ignore the fuel pressure sensor symptoms and keep driving the car.

At a point, starting your car and keeping it running will become a challenging task. This is because your vehicle will be stalling almost all the time.

In addition, you may be a severe threat when this stalling starts because it could stall when you are on a highway, posing a danger to you and other road users.

There’s a possibility of driving a car with a faulty or bad fuel pressure sensor, but this possibility is for a fuel pressure sensor that starts failing. If it is not attended to and fixed, the problem will worsen and be dangerous.

Also Read: How to Remove O2 Sensor without Socket (Step by Step)

How to Replace Your Car’s Fuel Pressure Sensor

fuel pressure sensor symptoms

Before we start this, it is pertinent to mention that if you do not have good experience in car repairs or mechanical repair skills, it will save you a lot to call a professional who is good at his job to come to carry out this repair.

The replacement of a bad fuel pressure sensor is not so tricky; however, if you are not familiar with car repairs, you may make things worse.

Let us assume you have the required skill and equipment to replace a bad fuel pressure sensor; below are the steps to carry out the replacement successfully.

  1. To avoid electrocuting and electronic damage, go to your car battery and unplug the negative cable.
  2. Some cars come with a plastic cover; remove it if you have one.
  3. To get to the fuel pressure sensor, you might need to remove the air intake.
  4. As you locate the fuel rail, also find the test port. Use an appropriate screwdriver for depressurizing the fuel rail; to do this, first, place a drip pan under the test port.
  5. Detach the mounting hardware and the electrical harness on the fuel pressure sensor, taking it out front of the fuel rail.
  6. Before installing the new fuel pressure sensor, clean the sensor electrical harness and fuel rail.
  7. As you install the new fuel pressure sensor, ensure proper tightening of the mounting hardware.
  8. Reconnect the electrical harness on the new fuel pressure sensor and attach it around the air intake if removed.
  9. Finally, connect the engine cover and cover adequately and reconnect the battery negative cable. If everything is done accordingly, you are set to start using your new fuel pressure sensor.

check out this video for more tips on how to replace the fuel pressure sensor

How to Test a Fuel Pressure Sensor

Get a good multimeter, then follow the steps below to test a fuel pressure sensor.

Step 1: Unplug the Sensor

To begin this procedure, you will need first to know where the sensor is located in your car; if you don’t know, consult your car manual for assistance.

When you finally find the sensor, unplug it from the vehicle. If you already know, go to the battery and disconnect it by just pulling the plug.

Step 2: Connect the Multimeter

When you locate the sensor and unplug it, start the car and move to the multimeter.

Ensure that the probes of the millimeter and adequately connected to the cable before starting the test. Don’t forget to connect the negative to the black probe and the positive to the red probe.

As soon as this connection is adequately done, check on the screen, you will discover the multimeter will begin to display values.

You will now have to know the correct voltage specification by consulting the manual; that is how you know if the values you are getting from the multimeter are good or bad.

Step 3: Compare the Results

After knowing the right voltage, look at the reading on the multimeter, compare the right voltage and what’s on the multimeter. Is the range close, behind, or far apart?

If you are getting wrong values, your sensor is not working correctly, or there’s an obstacle stopping your sensor from getting the correct readings.

Step 4: Check the Wiring

If after comparing and the values are correct, it gives you one step clear and saves you from carrying out a full investigation of the new pressure sensor.

The next thing to do after you are sure the sensor is working correctly is to check the wiring. It is one of the common problems most drivers or car owners face, so there is no cause for alarm.

Examine the wiring, disconnect and connect back all the sensor-related wiring; this ensures that the wirings are okay and adequately placed.

Remember that testing wiring is better than using the toolbox that comes with your car; this is because they are specifically designed for your vehicle and will give more accurate results.

When you cannot resolve the problem, take your car to a good car technician.

Step 5: Take Precautions

Avoiding trouble with a car is better than fixing the trouble. Therefore to avoid this problem, you will need to get a good fuel injection maintenance kit.

This kit comes with cleansing tools that will help ensure your sensors are clean and free from obstacles; they also help clear all abnormal pressure build-up.

This is highly essential and must be implemented because clogged fuel lines and dirty fuel filters are the primary causes of fuel system failure, which leads to poor engine performance and a shortage of lifespan of the car.

Also Read: How To Test An Alternator (3 Best Ways)

How Much Does Fuel Pressure Sensor Replacement Cost?

The cost of replacing a fuel rail pressure sensor is around $200-$400, depending on the car model. The price of the sensor itself is about $50-$120, while the labor rates should be around $150-$250. Also, note that location and labor service rate can influence these prices.

Frequently Asked Questions – Fuel Pressure Sensor Symptoms

What Happens if the Fuel Rail Pressure Sensor Goes Bad?

When the rail pressure sensor gets bad, the AF ratio is affected, and the engine will either get excess or less fuel. In whatever way, it reduces the engine’s performance, causing either sluggish acceleration or engine stalling.

Can You Drive With a Bad Fuel Rail Pressure Sensor?

If the problem is not that so bad, theoretically, you can. You can still drive your car to a mechanic with ease when the car fuel pressure sensor starts to fail, but the problem will worsen if you ignore the signs and keep using it.

Can a Fuel Rail Sensor Be Cleaned?

In rare cases, cleaning of fuel rail pressure sensor can help solve the problem of failing the sensor; this is by removing the dirt causing the sensor so malfunction or stop working. However, this does not always happen, and replacing the old sensor with a new one is more often the solution.

What Causes High Pressure in the Fuel Rail?

When the fuel pressure sensor is faulty or damaged, the air-fuel ratio will be altered, causing excess fuel or low fuel. Therefore, the ability to not regulate the fuel can cause high-pressure fuel in the rail. Also, a blocked return line can cause this symptom.

Can a Clogged Fuel Filter Cause Low Fuel Pressure?

When your car fuel filter is clogged, it can cause many things such as low fuel pressure, harsh engine idling, poor fuel mileage, and turn on the check engine light. The sign of your check engine is for the mechanic as soon as possible.

How Much Does It Cost to Replace a Fuel Rail Pressure Sensor?

The cost of replacing a fuel rail pressure sensor is around $200-$400, depending on the car model. The price of the sensor itself is about $50-$120, while the labor charge should be around $150-$250. Also, note that location and labor service rate can influence these prices.

Conclusion

The functionality and performance of a car engine can depend on how accurate the fuel rail pressure sensor is working.

For this, you must not joke with the fuel pressure sensor symptoms mentioned above and if you cannot fix the problem yourself, make sure you take the car to a mechanic or a technician as soon as possible.

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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