Black Smoke: Excessive black smoke from the muffler is almost always due to a rich fuel mixture and will produce high CO, and consequently high HC during the smog check or inspection.
White Smoke: A vehicle emitting excessive white smoke from the tailpipe may have a burned or blown head gasket. A blown head gasket may cause overheating and high NOx emissions. Most often the level of NOx produced will be twice the allowed limit, rendering your vehicle as a gross polluter or HEP.
California Smog Check Program applies to the following vehicles - A smog certificate will be required to operate these vehicles on public roadways: Acura, Alfa Romeo, Aston Martin, Audi, BMW, Bentley, Buick, Cadillac, Chevrolet, Chrysler, Lamborghini, Daihatsu, Dodge, Eagle, Ferrari, Ford, GMC, Geo, Honda, Hummer, Hyundai, Infiniti, International, Isuzu, Jaguar, Jeep, Kia, Daewoo, Land Rover, Lexus, Lincoln, Lotus, Maserati, Maybach, Mazda, Mercedes Benz, Mercury, Mini, Mitsubishi, Morgan, Nissan, Oldsmobile, Peugeot, Plymouth, Pontiac, Porsche, Rolls-Royce, Saab, Saturn, Scion, Smart, Sterling, Subaru, Suzuki, Toyota, Volkswagen, VW, Volvo.