Yes, if you get caught. No, if you don't. But if you live in an area that requires periodic emissions testing, you probably won't get past an emissions check with missing or disconnected emission controls.
WARNING: Federal law makes it illegal for ANYONE to tamper with, disconnect, remove or otherwise render inoperative ANY emissions-related control device. The Environmental Protection Agency and most states have actually been rather lax about enforcing this rule on motorists, but they haven't hesitated to nail professional service facilities that have been guilty of tampering. Even so, the fines can be hefty. A violation may make you liable for up to a $2,500 fine!
The federal anti-tampering law does not, however, apply to race cars that are not operated on the street, other full-time off-road vehicles, show cars that are not street driven, or vehicles not factory equipped with emission controls (most 1967 and earlier vehicles). So that exempts all antique cars, and most classic cars and muscle cars.
Revisions to the Clean Air Act in 1990 further broadened the definition of emissions tampering to include virtually ANY type of engine or exhaust system modification that alters what comes out the tailpipe. That means any nonstock aftermarket part that is installed on your engine must be EPA-approved and emissions legal (except on the exempt vehicles previously noted).
Before the law was revised in 1990, it was only illegal for professional mechanics to remove or disconnect emission control devices. There was nothing to prevent a motorist from tampering with their own vehicles. That loophole has since been plugged.
Any of the following may be considered emissions tampering and get you into trouble:
Aftermarket parts manufacturers who make nonstock performance parts for engines, the fuel, ignition or exhaust systems must apply for special certification for any parts they want to sell as being emissions-legal. The California Air Resources Board (CARB) has been the leading government body in this respect, so most submit their proposals to CARB.
First, they must submit detailed proof in the form of laboratory dyno test that document their part does not have an adverse effect on exhaust emissions. These tests are very expensive and must conform with specified test procedures. CARB then reviews the data and may or may not ask for additional information and/or testing. If the product meets CARB's criteria, CARB issues an "executive order" (EO) number (also called an "exemption" number) certifying that the part is in compliance with the applicable clean air rules.
An EO number means the component can be legally manufactured, distributed, sold and installed on a street driven vehicle in the state of California. It also means the component is legally acceptable in all 50 states because the federal Environmental Protection Agency also recognizes the CARB exemption program as meeting their "Memorandum 1A" requirements for certifying emissions legal parts.
Virtually all stock replacement parts are emissions-legal regardless of who makes them. But if you're buying any nonstock performance parts, heed the following to make sure you're "safe" from an emissions standpoint:
* Look for wording on the box that says the product is emissions legal or emissions certified for street use in compliance with the EPA and/or CARB rules.
* Look for the EO (executive order) exemption number issued by the California Air Resources Board on the box, product or in the catalog. Remember, the product must have an EO number to be street legal.
* If there is no EO number and one is required to be street-legal, it cannot be legally installed on a street-driven vehicle. Period.