5 Symptoms of a Bad Fuel Rail Pressure Sensor in Your Diesel Engine

The fuel rail pressure sensor is mostly used with diesel engines, although there are some gasoline engines which have them too. This sensor is linked to the engine control unit, which is the central computer of a vehicle. The purpose of this sensor is to keep track of the fuel pressure which the fuel rail currently has on it. Once the sensor detects this information, the data gets transmitted to the engine control unit. From there, the computer will analyze the information and make the necessary changes to the timing of the fuel injections and the quantity of the fuel being injected.  This creates better gas mileage and an overall better engine performance.

The engine control unit will only send the amount of fuel that the engine needs. This is how the gas mileage is reduced. Not only that, it means fewer carbon emissions going into the atmosphere as well. Since most vehicles on the road today are made to be eco-friendly, this makes the fuel rail pressure sensor a vital component that must remain functional at all times.

The Top 5 Symptoms

If there is a problem with the fuel rail pressure sensor, the engine control unit is not going to be able to do its job properly. Then you will experience a series of symptoms which you can attribute to this sensor right away.

Below are the top 5 symptoms of a bad fuel rail pressure sensor.

Warning Light – When your fuel rail pressure sensor goes bad, the “Check Engine” warning light may illuminate on your dashboard. This light activates whenever the engine control unit detects an issue within the vehicle that affects the engine in some way. This doesn’t always mean the engine itself is bad, but rather something else in the vehicle which is not allowing it to do its job properly. You probably won’t know it is the fuel rail pressure sensor at first. You’ll need to experience the next 4 symptoms or take your vehicle to the mechanic in order to realize that the sensor is to blame.

Difficulty Starting Engine – If you have a bad fuel rail pressure sensor, the engine control unit won’t send the right amount of fuel to the engine. This will make it difficult to start your vehicle. When this problem first occurs, it will probably take a couple of cranks before the engine starts. But as the problem gets progressively worse, it will take more and more cranks. Eventually, the engine won’t start at all.

Weak Acceleration – When you step on the gas pedal and the vehicle does not accelerate faster, then you could have a bad fuel rail pressure sensor. The engine control unit is not able to transmit the signal properly to the fuel system because it gets inaccurate information from the sensor. That means it won’t know how to accommodate the demands being placed on the engine.

Stalling – Engine stalling might occur as the fuel rail pressure sensor goes from bad to worse. You will be driving and then suddenly, your engine will stall. This will make driving extremely difficult and it should motivate you to do something about it. Take your vehicle to the nearest auto shop right away and get your sensor replaced if that is the cause.

Bad Fuel Mileage – When your fuel rail pressure sensor does not work correctly, it will reduce your fuel economy and mileage considerably. Either your engine control unit will send too much fuel or not enough fuel to the combustion chamber. You will quickly notice more trips to the gas station and more money out of your pocket.


Read also:  Tips for Changing Spark Plugs

Good News

This is a sensor component that will malfunction over time, but there is good news for anyone who is having issues with this engine component. The good news is that when problems arise with the fuel rail pressure sensor, it is usually only the sensor that is going to require replacing and not the entire part itself. This means that people experiencing issues with their fuel rail sensor can feel relieved because they will likely only have to replace the sensor and not the whole thing. With that being said, there are some tell-tale signs that there may be an issue with a fuel rail pressure sensor. Knowing what to look for can help catch the problem early, and fix it before any complications arise.

2 thoughts on “5 Symptoms of a Bad Fuel Rail Pressure Sensor in Your Diesel Engine”

  1. I have replaced a new rail pressure sensor but the car still do not perform. What could be the challenges or next step

  2. Hi.I have an open vivaro 1,9 cdti the car does start properly when its cold it does pour too much fuel on the engine smoking all the way black smoke and it wouldn’t burn that diesel anymore as its too much then it will just stops for it to start again I must wait for at least 2 hours to start as diesel will be sinked.so its a problem to me I don’t know what could be the problem fuel rail pressure sensor or injectors.

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