I just read the EPA site over more carefully and it sounds like it will be much easier for conversion shops to legally do older vehicles and not run afoul of "tampering" prohibitions. However, that does nothing for Californians, where CARB rules trump the EPA and anything originally gasoline powered less than 25 years old has to be bone stock. It still floors me that a "tampering" inspection is relevant if the OBD and tailpipe sniffer tests pass.

 

See FAQ - Can I convert a vehicle in California? CA residents have the benefit of cleaner air from not using modern components because of the additional EO visual inspection requirement during annual e-tests.

My understanding is that the requirement for EPA-certified systems is directed towards commercial conversions. The individual vehicle owner could have installed a non-certified system without EPA prosecution previous to this EPA Final Ruling. If the vehicle owner ran into problems with a conversion and needed help from a repair shop, the vehicle repair shop could repair the alternative fuel system without any issues with the EPA.

The concerns for the vehicle owner are passing the annual emissions test and [not] being eligible for the federal tax credit. However, it is possible that the net cost of a conversion could be lower with a non-certified system and no tax credit than with an EPA-certified system and full tax credit.

 

thanks for the topic.