In some states -- such as California -- it's required that your vehicle pass a smog test. While the requirement is standard for all vehicles, older vehicles have a higher risk of failing the test. The older your car gets, the more oil and fuel it burns, sending fumes into the atmosphere. But, instead of resorting to costly repairs, try a few simple techniques that can help your car pass the test.
Give your car a tuneup. Start by changing the oil and the oil filter. Because the old oil has a higher hydrocarbon level, the oil change makes a big difference during a smog test. Also, replacing the air filter, cleaning the mass air flow sensor and changing the spark plugs and spark wires help the engine run better.
Check the exhaust pipes for any holes or other damage. Damaged exhaust pipes can cause exhaust gases to leak into the air. Repair any damage or replace the pipes before you take your car for a smog test.
Add fuel additives to your gas tank. Pour one small bottle into the tank when you fill your car with gas. The fuel additives remove carbon deposits caused by fuel.
Check tire pressure and add air if needed. Having the correct tire pressure helps your vehicle run properly. If your car doesn't have the proper tire pressure, your engine works harder and emits more toxins into the air.
Drive your car for approximately 30 minutes prior to the test. Your car runs at it best when it's warm, so it's important to drive until your engine is warm before taking a smog test.
Use premium fuel. Fill up with premium fuel before the smog test. Since premium fuel burns cleaner, you have a greater chance of passing the smog test if you use premium fuel.
