There are three sources of automotive pollutants; crankcase fumes, exhaust gases, and gasoline evaporation. The pollutants formed from these substances fall into three categories: unburned hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The equipment used to limit these pollutants is called emission control equipment.
Due to varying state, federal, and provincial regulations, specific emission control equipment may vary by area of sale. The U.S. emission equipment is divided into two categories: California and 49 State. In this section, the term "California" applies only to cars originally built to be sold in California. Some California emissions equipment is not shared with equipment installed on cars built to be sold in the other 49 states. Models built to be sold in Canada also have specific emissions equipment, although in many cases the 49 State and Canadian equipment is the same.
Both carbureted and fuel injected cars require an assortment of systems and devices to control emissions. Newer cars rely more heavily on computer management of many of the engine controls. This eliminates the many of the vacuum hoses and linkages around the engine. In the lists that follow, remember that not every component is found on every car.ECM CONTROLLED SYSTEMS
NON-ECM CONTROLLED SYSTEMS