Can you bypass a fuel rail pressure sensor?

This sensor monitors the fuel pressure present at the fuel rail within the engine. Though it plays a critical role in managing the engine, this component can at times prove problematic to a driver by triggering an unnecessary check engine light. This begs the question;

Can a fuel rail pressure sensor be bypassed?

The short answer is yes, though it’s a hit-or-miss kind of thing. You can actually do so by using a simple instrument called an “LED test light”. This tool can help you create the necessary resistance to the electrical circuit flowing to the sensor, thereby bypassing the sensor.

Advantages of Bypassing The Fuel Rail Pressure Sensor

1. Great Gas Mileage.

Bypassing the fuel rail pressure sensor can ensure a greater fuel economy sometimes. This is especially true if the sensor is erroneous and it’s sending false signals to the electronic control module regarding fuel usage.

2. Better Engine Performance

If the ECM doesn’t know exactly how much fuel the car is consuming and how much gas is needed to maintain the necessary speeds at any one time, the car will consume fuel extravagantly.

This will lead to bad engine performance such that you may witness poor power output and poor acceleration.

3. An Effective Fix for a Frequently Stalling Engine

If your engine is always stalling, bypassing the fuel rail pressure sensor may sometimes help resolve the problem. An unreliable fuel rail pressure sensor can mislead the car’s computer, which can in turn calculate the wrong air/fuel mixture ratio for the combustion process.

Consequently, this can affect the combustion cycle, leading to improper fuel burning and a hesitant or stalling engine.

4. Resolves Hard Starting

A lousy sensor can cause the fuel injectors to send excessive amounts of gas to the combustion chamber, which can lead to hard starting. Bypassing the sensor can help avoid this issue, resolving the hard starting problem.

5. Resolves Misfires

Engine misfire is a common sign of a bad fuel rail pressure sensor. Bypassing such a sensor means rendering it functionless. This eliminates the root cause of your misfires, resolving the problem effectively.

Disadvantages of Bypassing The Fuel Rail Pressure Sensor

  1. A fuel pressure sensor helps make your fuel pump last longer. Bypassing it, therefore, means jeopardizing your fuel pump’s lifespan.
  2. At idle, the need for excess fuel is reduced by the fuel rail pressure sensor. Bypassing the sensor, therefore, means your engine will use excess fuel at idle.
petrol engine with fuel pressure sensor and fuel regulator

How to Bypass The Fuel Rail Pressure Sensor

To bypass the fuel rail pressure sensor, you’ll first need an LED test light. Just as the name suggests, this is an instrument that can be used to test the soundness of various components of the engine including the fuel rail pressure sensor.

Consisting of a bulb connected to two test leads, it works by providing a visual indication of when voltage is present in a circuit.

To bypass the fuel rail pressure sensor, follow the two simple steps below;

  • STEP 1: Connect the LED test light to the sensor’s signal wire to add resistance.
  • STEP 2: Connect the alligator clip to the sensor’s ground wire.
  • STEP 3: Touch the signal wire with the test light probe to establish resistance. N/B: The test light should illuminate, showing that you’ve established resistance and bypassed the sensor.

How Much Does It Cost To Bypass The Fuel Rail Pressure Sensor?

It takes 10-15 minutes to bypass a bad fuel rail pressure sensor. Nonetheless, many mechanics charge $80 to $100 an hour, on average. Thus, you can expect to pay around $17-$21, all factors remaining constant.


The fuel rail pressure sensor is designed to read the fuel pressure and signal the ECM to send the required fuel pressure to the rail. If lousy, it can misread the pressure, and incorrectly advise the computer to adjust the fuel pressure.

This can result in a number of problems including extravagant fuel consumption, and poor engine performance. Apart from that, it can also cause engine misfires, hard starts, and stalls, not to mention, reduce your fuel pump’s lifespan.

To avoid this problem, you could bypass the sensor. You can do this on your own by following the simple steps above, or take the car to your mechanic to help with that.

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