Any vehicle built before 1975 is exempt from the CA smog test. For later model vehicles which do require smog inspections... California allows engine swaps when the engine and emission control system which is to be installed are in an engine-chassis configuration certified by the California Air Resources Board (ARB) or U.S. Environmental Protection Agency (EPA). The engine you plan on using to convert your Jeep from gasoline to diesel must meet or exceed the requirements for the year and class of your vehicle. Basically, you must be either improving or keeping the same level of emission output which the Jeep currently produces. By changing or swapping the engine you may not degrade the vehicle's emissions output.
Please visit the
California Air Resources Board to look up diesel engine California certification. After the swap is complete the engine change must be inspected by an official referee station and must have a Bureau of Automotive Repair (BAR) Vehicle Identification Label affixed to the doorpost.
