How Much Does A Knock Sensor Effect Fuel Economy

Posted in Crank, Oil and Piston | Asked on Jun 5, 2010

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There are 2 Answers for "How Much Does A Knock Sensor Effect Fuel Economy"

  1. bobweb says:

    It controls the ignition spark advance, so if the sensor says that the engine is knocking (whether it truly is or isn’t knocking), then the spark advance will be retarded and your gas mileage will be reduced. You will also lose power on acceleration.

  2. Country Boy says:

    Occasionally knock sensors whack-out other systems in the car. The transmission won’t shift correctly, low octane fuel will make the fuel mixture pre-ignite which causes excess heat in the combustion chambers. Valves, seats, pistons and top rings catch merry hell. Nobody knows how your spark advance works without a properly working knock sensor. It would be fun to stick on a properly sized MSD degree tape on your dampener pulley and check it with an inductive timing light throughout the normal RPM range.

    It’s the knock sensors job to regulate spark advance according to the grade of fuel you’re using. Low octane gas causes reduced spark advance when the sensor is working properly. When this happens fuel economy and power suffers at all engine speeds.

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