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Knock, Knock! It’s Your Engine

Knock, knock jokes may be funny but it’s certainly no laughing matter when the knocking is coming from your engine. A knock or pinging sound could be indicative of a few things but one thing is for sure, the engine may be struggling to operate efficiently. Any unusual sound stemming from the engine could spell trouble if left unresolved. Read on to find out the answer to the question you may be asking, “Why does my engine knock or ping?” and what you can do to prevent it.

The Importance of a Knock Sensor

Knocks are generally the result of improper octane, poor fuel quality, or engine or sensor issues. Each vehicle is equipped with a knock sensor that communicates to the vehicle’s computer to adjust the timing to compensate for any problems have been identified. The sensor creates a voltage signal based on the vibrations/noises caused by a problem. The computer takes the information to adjust timing when a spark knock occurs. Knock sensors are typically located on the engine block, cylinder head, or intake manifold. This allows it to sense the vibrations caused by the engine knock or combustion. The PCM, or powertrain control module, utilizes the signal to adjust the ignition timing and prevent pre-ignition, if necessary. If the knock sensor is not working properly, you may notice such symptoms as:

    • Check engine light illuminating
    • Decrease in mileage
    • Loss of power
    • Decrease in acceleration
    • Emitting higher emissions

Poor Fuel Quality or Incorrect Fuel Type

The knock sensors job is vital as it is basically the computer’s ear to the engine and determines whether or not it is working properly. If the vehicle consumes poor quality fuel and the computer is not able to adjust the timing the engine begins to start knocking. Some vehicles with higher performance engines require premium fuels with a higher octane. Utilizing the incorrect fuel type for your vehicle could produce a less than satisfactory performance. Octane is the measure of how much temperature and pressure the fuel can tolerate before igniting. The higher the number, the less likely the vehicle is to ignite inaccurately, which increases efficiency, performance, and a reduction in emissions. This means your vehicle will get better mileage and power and is better for the environment. Consult your vehicle owner’s manual to determine the correct fuel for your vehicle.

Pinging Sounds

While pinging is rare for newer vehicles, it does still occur with older cars, most often because of the EGR valve, or exhaust gas recirculation. The EGR valve’s function is to reduce emissions in gasoline and diesel engines by re-circulating a fraction of the engine’s exhaust back into the engine cylinders. The exhaust gases are re-burned through a combustion chamber to reduce combustion temperature. High combustion temperature creates nitrogen oxide (NOx), a chemical byproduct. High levels of nitrogen oxide result in a failed emissions test. While pinging is most often the result of a malfunctioning EGR valve, there are other factors that may be causing the pinging sound such as:

    • Low octane
    • Timing is off
    • Carbon build-up
    • Poor fuel quality

While most of these issues are common with both older and newer vehicles, newer vehicles are equipped with improved technology in combustion and EGR valves are becoming an antiquated component for emission reduction.

Engine Care You Can Count On

Whether your vehicle is just a year or two old or has been on the road for many years, if your check engine light has come on or the engine is running rough, call on the experts at Sun Auto Service. Our ASE Certified Technicians are able to scan your vehicle’s stored computer codes and determine what is causing your engine’s knocking or pinging sounds. Don’t wait until your engine is under total duress, bring your vehicle to any of our convenient service centers in Nevada or Texas, right away. The engine is a vital component of your vehicle and needs to be cared for by a technician you trust most. That’s what you’ll find with Sun Auto Service! Plus, we use OEM or equivalent parts, guarantee all our work in writing, free towing with major repairs, and guarantee same day service, in most cases.  For more information on our FREE engine diagnostic scan service, click here.