The air filter is one part of the car that most drivers don't give much thought to, but did you know that it has a huge effect on your car's performance? This is because your car's engine needs clean air to operate efficiently, and it is the filter that cleans the air entering the engine. That is why you should be aware of the signs and symptoms of a dirty air filter, which include things like:
Unusual Engine Sound and Performance
A car engine requires a precise mixture of air and fuel in order to run efficiently. Unfortunately, a dirty air filter will interfere with this ratio because not enough air will be getting into the engine. In such a case, the fuel won't be completely combusted in the engine. Some of the mixture (considering that they are products of incomplete combustion) may ignite outside the combustion chamber, creating what is called a misfiring engine. In many cases, you may also notice the engine stuttering and generally not performing as well as it usually does.
Reduced Fuel Economy
If the engine is not getting as much air as it should, combustion will be incomplete and engine power will be reduced; the engine may then try to compensate for the loss of power by burning more fuel. Unfortunately, it is not fuel that your car needs at this point, but rather a good air-fuel mixture. This is particularly true with old cars (decades old) that still rely on carburetors -- the fuel-efficiency performance in newer cars should be marginal.
Sooty Smoke in the Exhaust
As hinted above, running a car engine when the air filter is clogged leads to incomplete combustion. Incomplete combustion means the exhaust your car will be producing will have a different composition from the one it usually has when the air filter is clean. For example, you should expect more carbon than usual, which will manifest itself in the form of soot. Therefore, you should suspect a dirty air filter if your car is producing black exhaust.
Gasoline Smell When Starting the Car
Lastly, you should also suspect a dirty air filter if you can smell the characteristic gasoline smell when starting the car. In such a case, it is the unburned fuel in the exhaust that you will smell. This happens because the carburetor or fuel injection system is getting inadequate oxygen that cannot help it combust all the fuel. In fact, this is the reason your car will experience decreased fuel consumption if its filter is dirty – as previously discussed.
If you think your air filter is dirty and needs to be replaced, contact your local auto repair shop for more information and to schedule an appointment.