What is a Fuel Rail Pressure Sensor?

What is a Fuel Rail Pressure Sensor?

If you happen to have a vehicle that still draws power from gas, it comes integrated with a complex fuel delivery system that makes the whole unit function and is composed of:

  • injectors
  • pumps
  • sensors
  • control units

amongst other parts.

The vehicle’s fuel system is responsible for two main kinds of operations

  • How it puts the fuel to work
  • What it does with the remaining leftovers  

When improperly handled, the remaining fuel can find its way through other components, causing damage that will permanently affect the car’s performance.

The fuel rail pressure sensor is particularly responsible for controlling the exact evaporative emissions of the system and is located in the fuel rail to limit the leftover fuel that’s let inside the fuel line by reading the rail’s internal pressure, providing for the correct operation of the vehicle based on the throttle levels.

When a pressure drop takes place in the rail, the sensor has a negative pressure supply mechanism that will alert the main engine control unit about the rail’s pressure drop, resuming the pressure within the pump to regain pressure balance.

This is possible due to the utilization of a specific valve that keeps the fuel pressure. That’s why this sensor is such an elemental component, because it basically guarantees the successful operation of an internal combustion engine in a gas vehicle.

Failure Symptoms

A flashing check engine normally lights up which might indicate a bad fuel rail pressure sensor. When caught in early stages, the problem will quickly be solved by a proper sensor replacement.

However, there are some other signs in addition to the warning signs accentuated by the check engine light that might indicate a fuel rail sensor malfunction such as:

  • engine hesitation (when starting/accelerating)
  • rough idling
  • stalling and difficulty starting



Fuel Rail Pressure SensorReplacement Process

Once properly diagnosed, a faulty fuel rail sensor can be replaced by following the next steps:

  1. Your car must be under a flat, hard surface.
  2. Install a 9V saver into the cigarette adapter if you have one, so the diagnosis computer endures the whole process.
  3. Take the battery out.
  4. Remove the engine cover and any brackets that may cover up the fuel rail sensor. When having an intake on the engine mounted transversely or getting in the way of the fuel rail sensor, taking it apart before removing the fuel rail sensor.
  5. Look for the test port placed on the fuel rail and make sure you use the proper fuel hose quick tool to release the fuel hose from the fuel rail. This will release fuel rail built up pressure.
  6. Carefully take the harness away from the fuel rail sensor, then pull the mounting hardware away from the fuel rail sensor.
  7. Take the old fuel rail sensor apart of the fuel rail and clean the fuel rail with a lint free cloth.
  8. Install the new sensor onto the fuel rail. Put the mounting hardware finger back together with a screwdriver.
  9. Reconnect the fuel rail sensor harness to the sensor and reinstall brackets. Install the intake that got removed. Ensure to replace the gaskets or o-rings to seal the intake to the engine.
  10. Reinstall the intake and the engine cover.
  11. Check for any leaks.
  12. Drive the vehicle and listen carefully if there’s any odd noise coming from the engine cylinders and feel for any vibrations as well.
  13. Check the dash for fuel level or for any engine light to appear.

If you want to know more about the fuel rail pressure sensor, visit our website for more information.


Bryce Newell is an automotive enthusiast who loves to write about the latest news, products, and DIY projects. While Bryce is an amateur in the field, he is passionate about cars and has been since he spent weekends in the garage helping his dad rebuild a 68 Dodge Charger as a kid.

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