What Is a Knock Sensor? Everything You Need To Know

Knock Sensor

A modern-day vehicle has some systems in place that can assert the state of damage; the system also can identify many other anomalies that go wrong in a car’s power plant. These systems are the sensors. With them in place, you do not need to first guess or second guess the problems at hand. They lead car owners to accurate conclusions on challenges.

A knock sensor is one of the engine sensors in the car. It essentially helps to detect the irregular vibrations and sounds that come from the engine block. With these sensors in place, you can’t ignore critical warning signs that point to ongoing damage. Thanks to technology, sensors are here to detect knock in the air and fluid; it can also identity vibrations and detect and oxygen levels, as well as many other faults in your car.

What is a Knock Sensor?

A knock sensor is a piece of the automotive device. It sits on the surface of the lower part of the engine. This device mainly keeps an ear out for abnormal motions and sounds originating from the lower parts of the engine.

The notifications convert to electricity and that the electrical systems transmit to the engine’s control center. This center determines whether to put on the check engine light or close down the engine. It will decide whether to vary the strength and timing of the ignition.

The knock sensor plays a crucial role in determining not just the anomaly with the engine. It also intimates you on how bad the situation is by taking some crucial steps to protect your engine.

The knock sensor ensures that fuel is consumed appropriately by the engine. It does this by leveling the air to fluid ratios that the engine ingests. This way, it will save your engine more stress and invariably saving your pocket more money.

The knock sensor can perceive some sounds that are inaudible to the driver’s ears. When it does, the sensor can delay the spark plug timing to avoid engine damage.

How Does a Knock Sensor Work?

A good number of knock sensors use the principle of piezoelectric elements. This effect entails transforming a mechanical signal into an electrical one. This is how the knock sensors can feel the challenge within the mechanical parts of the engine block. The block runs on the difference in fluid pressure and quantity, vibration, and frequency. 

When they sense mechanical problems in any of these, they also can transform it into an electrical signal. In addition, they will deliver the results to the Engine Control Unit (ECU) for interpretation and appropriate actions.

There are two kinds of knock sensors: pressure measures and vibration detectors. The vibration detectors are the most popular in the market.

Symptoms of a Bad Knock Sensor

Of course, you can drive your car with a damaged knock sensor or even without any sensor at all. But honestly, why risk losing your engine for such a flimsy reason? Ultimately, driving without an engine knock sensor would earn you a much more costly problem.

Keep the following symptoms in mind. This way, you’ll be able to identify whatever is wrong with the engine knock sensor.

  • Reduction in acceleration levels

A decreased acceleration level indicates that something is wrong with the functioning of your knock sensor. Acceleration decreases when there is a lack of power; this slows down the timing of the engine and reduces fuel mileage. As a result, it incapacitates the power of the transmission to drive. There’s also a likelihood that of the presence of clog in the fuel injector.

  • Low fuel efficiency

This is a common symptom when your knock sensor fails. Typically, the knock sensor should cause a delay in the spark of the ignition; this will prevent detonation. However, a failed knock sensor will allow detonation.

  • The Check Engine light illuminates

Theengine light will come once the knock sensor is faulty. This occurs because the sensor can detect certain sounds or recognize an abnormality the engine is producing. 

  • Loss of power

Most often, the vehicle engine will lose due to their high-compression feature. The engine will also become insecure as a result of a flex-fuel engine. What the loss of power does is to hamper the transmission from gaining drive. This way, it will decrease the rate of engine timing.

  • A general decline in engine performance

There will be a general performance decline in the engine once the knock sensor fails. The knock sensor input determines how much power an engine receives or loses. This operation will depend on the octane limit of the engine.

How to Replace a Knock Sensor & Cost?

Knock sensors wear down normally when they have been in use for a long. So, replacing the engine knock sensor should be a part of your budget. The sensor can cost anything between $100 to $200 then add the mechanic’s fee to that.

Top Brands of a Knock Sensor

If you want to get a new knock sensor, the best thing is to find the best brands. This will help prevent wasting money to get another one. We have also included a thing or two about the prices of these engine sensors. Insight of the prices can make prepare your budget.

  • Honda offers a new knock engine sensor numbered 30530-PPL-A01 at a rate of $85 USD.
  • Hyundai gives its sensor on sale at a budget-friendly rate of $20 USD. Their engine knock sensor 39250-2G100 is quality even at the rate it is sold for.
  • General Motors sensors cost around $35 USD, and their products are renowned for quality and durability. You can find them online, making it easy for you to access their products.
  • Huijin knock sensor goes for $12 USD, but it isn’t compatible with every engine. Only Nisan 200sx, quest, Lucino, Tsuru, and other selected vehicles can use this sensor.
  • Toyota sells for a sum of $141 USD, and its manufacture number is 89615-12090. It ensures quality and durability.

Final Thoughts

A knock sensor is part you may never guess is having an issue. The relevance of this part of the engine to the overall functions of the car is enormous. Hence, it requires that you pay attention to earlier warning signs.