enhanced smog test counties california

Optimum fuel combustion is achieved when the engine can maintain a 14.7:1 air/fuel ratio during the combustion process with a constant variation +/- 5% to assist the catalytic converter operation. After the 1973 model year, automobile manufacturers were required to factory install NOx devices (usually in the form of EGR valves) on all cars sold in California. After the repairs are done, another test will be performed to see if the repairs brought your vehicle up to standard. [4], Residents in certain counties, primarily rural ones, are normally exempt from the smog inspection requirements. It may not display this or other websites correctly. a. For new residents, the smog check is required before you can register your vehicle. If you are in a enhanced or basic program area you have to get a smog check inspection every other year.