97 Mustang GT Camshaft Upgrade

The federal tampering prohibition is contained in section 203(a)(3) of the Clean Air Act (Act), 42 U.S.C. 7522(a)(3). Section 203(a)(3)(A) of the Act prohibits any person from removing or rendering inoperative any device or element of design installed on or in any motor vehicle in compliance with regulations under Title II of the Act (i.e., regulations requiring certification that vehicles meet federal emissions standards). The maximum civil penalty for a violation of this section by a manufacturer or dealer is $25,000; for any other person, $2,500. Accordingly, any change from the original certified configuration of a vehicle or engine, or the manufacture or sale of a non-original equipment aftermarket part or system could be considered a violation of section 203(a)(3) of the Act. This would include modifications to the fuel delivery system.

Here is a sampling of this interpretation:

• Can I remove a catalytic converter from a vehicle that is used only for "off-road" driving?
  
  No. The tampering prohibition discussed in Answer #1 applies to this situation as well. The federal tampering prohibition pertains to "motor vehicles," which are defined by section 216(2) of the Act as "any self-propelled vehicle designed for transporting persons or property on a street or highway." A light-duty vehicle manufacturer certifies an engine-chassis configuration as meeting the applicable emissions standards for motor vehicles manufactured in a given model year, and it is not legal for anyone to "de-certify" a motor vehicle for "off-road" use.
  [I wonder if NASCAR knows about this?]
  
• Is it tampering to install a dual exhaust system on a vehicle originally equipped with a single exhaust?
  
  Yes. The general rule is that a motor vehicle emission control system (which includes the exhaust configuration) may not be changed from an EPA certified configuration without subjecting the repair shop to liability for violating the federal tampering prohibition. The exhaust system configuration, including the location of the converters, and exhaust pipe diameter and length, are items specified by the manufacturer because engines and some of the associated emissions systems are generally affected by the exhaust system backpressure, which subsequently affects vehicle emissions. The installation of a dual exhaust system with two converters would, therefore, be considered tampering. ? It would not be considered tampering to install a dual exhaust system with two converters if the vehicle manufacturer certified an identical engine-chassis configuration for the vehicle model year or newer that includes such an exhaust configuration.
  
• If I pass a standard state inspection test (i.e., a "sniff" or Inspection/Maintenance Test) is my vehicle legal?
  
  No. The testing that the manufacturers perform to demonstrate compliance with Federal standards is more comprehensive and accurate than the idle tests used by the Inspection/Maintenance (I/M) programs. For example, the procedures for light-duty cars and trucks require the vehicles to undergo prescribed sequences of fueling, parking, and operating in order to simulate an average trip in an urban area. Heavy-duty engine testing requires a similar transient mode testing procedure. During these procedures, the emissions are sampled continuously over the entire test cycle for subsequent analyses of specific components by prescribed analytical techniques. These procedures are more representative of in-use operation than any state or locally run idle emissions test.
  
  Idle emissions tests used by state I/M programs are designed merely as screening tests for identifying gross emitting vehicles which have not had proper maintenance (spark plug replacements, air filter changes, timing adjustments, carburetion adjustments, etc.), and not to detect whether specific emission control components are present and operational. The tests usually only involve the insertion of a probe into the tail-pipe of the vehicle while the vehicle is idling and instantaneously measuring the exhaust emissions. These tests are not as stringent or accurate as the Federal test procedures and the results are not comparable. It would be inaccurate to assume that just because a vehicle "passes" an idle test that it could also pass Federal standards.
  

• Memorandum 1A
• Steve Albrink's November 14, 1997 Letter
• Steve Albrink's March 20, 1995 Letter
• April 30, 1996 Engine Change Letter
• Engine Switching Fact Sheet
• 1992? Letter to Congressman Boucher
• Exhaust Repair Guidelines
• 1996 Letter to Senator Herb Kohl
• Guidance that Individuals Can Be Fined
• Letter to Undercar Digest
• Another Undercar Letter, in Q&A Format