If you have seen any type of auto racing, than you may have seen the K & N air filter stickers on some of the race cars.
K & N air filters work great for high performance motor sports, water craft and off-road vehicles, but they are not good to use on a regular engine. Many engines today use a “MAF” sensor (Mass Air Flow Sensor) to measure incoming air going into the engine. The engine computer uses the data from the MAF sensor to adjust engine timing, fuel injection, and transmission shift points.
K & N air filters may improve engine output only by a small percentage. The way K & N does this, is by using a less restrictive woven mesh. The woven mesh is coated with a light spray of oil. The oil is used to help trap dirt in the mesh. When an engine is running, it is drawing air past the oil coated mesh. Then the oily air flows past the MAF sensor, coating the sensor in a fine oil. The fine oil attracts dirt and contaminates the MAF sensor element, just like the sensor in the video above.
Only OE quality filters should be used with a MAF systems. A quality filter will prevent the sensor from getting all clogged up with dirt. The video shows me cleaning a GM MAF sensor gently with a Q-tip dipped in alcohol. The client thought they needed a tune up. The car was running poorly and pinging, but the computer had no code and no check engine light on.
Yes, the engine needed service, but the heart of the poor operation was a very dirty MAF sensor due to an oil soaked K & N oil filter.
