In order for a vehicle’s internal combustion engine to run successfully, many different parts are used in the engine’s fuel assembly. such as a fuel pump, fuel filter, fuel injector, fuel common rail, and fuel pressure sensor. All these parts play an important role in the successful operation of the engine.
Through this article, we will get detailed information about fuel pressure sensors. Like, what is a fuel pressure sensor? Symptoms of a bad fuel pressure sensor, and how much can a replacement cost?
What Is Fuel Pressure Sensor?
The fuel pressure sensor is a vital component in the vehicle’s fuel system that measures the fuel pressure within the fuel rail and sends this data to the engine control module, and the ECU optimizes the fuel injection timing based on this data. This ensures that the engine gets the right amount of fuel for efficient combustion. Typically, the fuel pressure sensor is installed at one end of the fuel rail, where it detects fuel pressure.
Symptoms Of A Bad Fuel Pressure Sensor
Symptoms of a bad fuel pressure sensor include a check engine light, an engine that won’t start, prolonged cranking, engine hunting, rough idle, engine misfiring, low engine power performance, and fuel injector knocking.
Let us know the symptoms of a bad fuel pressure sensor in detail so that you do not have any confusion about the symptoms related to its malfunction.
1. Check Engine Light On
The first thing you may see as a warning when the vehicle is having a sensor related problem is the check engine light on the vehicle’s cluster meter. You will need to scan your vehicle with the help of a digital OBD scanner to know why this check engine light is on. which will give you information about the reason why the check engine light is on, and you will be able to troubleshoot this problem.
2. Engine Not Starting
Sometimes the engine will not start when the fuel pressure sensor is bad. A bad fuel pressure sensor is unable to signal the engine control module a reading of the fuel pressure in the fuel rail. Due to this, the Engine Control Module turns off the power pulse to the sensor on the fuel injector. Thereby, the fuel injector stops injecting fuel into the internal combustion chamber of the engine. Hence the engine does not start even during prolonged cranking of the engine.
3. Prolonged Cracking Engine Starting
In some cases a bad fuel pressure sensor can cause the engine to start very hard followed by prolonged cracking. Because a bad fuel pressure sensor causes the engine control module of the vehicle to give an incorrect reading of fuel pressure in the fuel common rail. This causes the ECM to send the wrong amount of fuel to the fuel injectors with incorrect timing. Due to this, the fuel mixture in the engine is not ignited in the right quantity or according to the position of the piston.
Due to this, the fuel combustion process in the internal combustion chamber of the engine is interrupted. So the engine starts hard after prolonged cracking due to a bad fuel pressure sensor. However, these symptoms can also occur when the crankshaft and camshaft sensors are bad.
4. Engine Hunting Issue
The most common symptom of a bad fuel pressure sensor is engine hunting. A bad fuel pressure sensor causes the engine speed to constantly go up and down at the idle position. Because a bad fuel pressure sensor is unable to signal the correct fuel pressure reading in the fuel rail to the Engine Control Module.
And the ECU starts sending more or less fuel to the fuel injector without signal. Due to which the engine speed starts up/down continuously even at idle position. However, these symptoms can also occur when the alternator’s output supply to the engine is high or low. Therefore, to troubleshoot this engine problem, you must first examine it.
5. Rough Idle & RPM Needle Up/Down
Your vehicle’s engine may be having rough idle problems due to a faulty fuel pressure sensor and the engine will start at an abnormal speed in the idle position. Along with this, when the engine is started in the idle position, the RPM needle in the cluster meter of your vehicle will start going up and down. Because of a bad fuel pressure sensor, the Engine Control Module is unable to keep the engine RPM constant at the idle position.
6. Engine Misfire Issue
A bad or faulty fuel pressure sensor can cause the engine to misfire upon acceleration. Because of a bad fuel pressure sensor, the vehicle’s Engine Control Module is not able to send fuel to the fuel injectors in sufficient quantity and with the correct timing.
Acceleration of the engine requires more fuel and a faster power pulse supply to the fuel injectors. But a bad fuel pressure sensor causes the ECM to be unable to carry out fuel firing orders according to engine speed. Due to this, the engine starts showing signs of misfiring at the time of acceleration. However, there can be many other reasons for an engine misfiring. To get rid of this problem, its causes should be thoroughly investigated.
7. Low Power Performance
A poor or faulty fuel pressure sensor can cause a reduction in engine performance to be felt. Because a bad fuel pressure sensor is not able to send a signal to the Engine Control Module reading the fuel pressure in the fuel common rail.
As a result, the ECM is not able to send a power pulse and the correct amount of fuel to the fuel injectors with the correct timing according to the position of the engine’s pistons. which causes the fuel combustion process in the internal combustion chamber of the engine to get disrupted. Due to which the fuel is not ignited in sufficient quantity. Therefore, a poor fuel pressure sensor can cause a reduction in engine performance to be felt.
8. Fuel Injector Knocking
Often in the engines of diesel vehicles, the fuel injector starts knocking during acceleration due to a bad or faulty fuel pressure sensor, or the fuel injector starts knocking continuously. Because the fuel pressure signal in the fuel common rail of the bad fuel pressure sensor is not being received by the ECM. Due to this, the ECM does not send a power pulse to the fuel injector according to fuel pressure. which the fuel injector starts knocking due to high fuel pressure and the fuel injector power sensor not working properly.
How Does The Fuel Pressure Sensor Work?
The fuel pressure sensor sends a signal of the fuel pressure reading in the engine common rail to the ECU of the vehicle. Based on that, the ECU controls the amount of fuel in the fuel injectors and operates the fuel injector pulse.
The fuel pressure sensor then signals the fuel pressure reading on the fuel common rail to the ECM. Thereby, the ECU adjusts the amount of fuel and power pulse supplied to the fuel injectors according to the engine speed, which in turn increases the speed when the engine is successfully accelerated.
Where Is The Fuel Rail Pressure Sensor Located?
The fuel pressure sensor is usually located on the fuel common rail on the engine. From where the fuel pressure sensor sends a fuel pressure signal to the engine control module in the fuel common rail The fuel common rail is often located near the intake manifold of the engine. But some vehicle models may have the fuel pressure sensor located somewhere in the fuel line. But this is seen in very few vehicle models.
Fuel Pressure Sensor Fault Trouble Codes
- P0190 – “Fuel Rail Pressure Sensor Circuit Malfunction”
- P0191 – “Fuel Rail Pressure Sensor “A” Circuit Range/Performance”
- P0192 – “Rail Pressure Sensor A Circuit Low Input”
- P0193 – “Rail Pressure Sensor A Circuit Low High”
- P0194 – “Fuel Rail Pressure Sensor “A” Circuit Intermittent/Erratic”
Fuel Pressure Sensor Replacement Cost
Fuel pressure sensor replacement cost depends on the make and model of the vehicle and the location of the mechanic to perform the replacement.
On average, the cost of a replacement fuel pressure sensor for common vehicles can range from $160 to over $260. This cost may include the mechanic’s labor costs. A fuel pressure sensor can cost $100 to $150, and the labor cost to have it replaced by a mechanic can range from $60 to $110.
Q. – How do you check fuel pressure sensor?
A. – To check the fuel pressure sensor, first disconnect the fuel sensor wire connector. Now start the engine. However, your vehicle’s engine may now start with a prolonged crank. Connect the fuel pressure sensor lead to the multimeter lead. Check the fuel pressure reading on the multimeter with the engine running.
Q. – How much does it cost to replace the fuel pressure sensor?
A. – Fuel pressure sensor replacement costs for vehicles can range anywhere from $160 to $260. This cost includes the labor cost of having the fuel pressure sensor replaced by a mechanic.
Q. – What happens when fuel pressure is low?
A. – A broken or failing fuel pressure sensor can cause a variety of symptoms in a vehicle. such as engine misfire, engine vibration, engine stalling, acceleration hesitation, and low power performance.
Banty is the owner of Autorepairszone.com & is also a vehicle mechanic by profession. We have almost 12 years of experience in the field of automotive repair, and we strive to provide you with accurate information about vehicle malfunctions and repairs based on our experience.