# COMAR Title 11 — Department of Transportation ## Subtitle 14 — Motor Vehicle Administration — Vehicle Inspections ### Chapter 06 — Emissions Equipment Standards **Authority:** Transportation Article, §§12-104(b) and 23-104, Annotated Code of Maryland **Administrative History:** Effective date: April 1, 1991 (18:6 Md. R. 686) #### Regulation .01 Applicability. *COMAR 11.14.06.01* The standards, requirements, and procedures set forth in this chapter are applicable to equipment originally installed by a vehicle manufacturer or required by federal or State requirements on all vehicles designated as a 1968 or newer model year. Each vehicle has an emissions label in the engine compartment which indicates the emissions equipment originally installed on the vehicle. If the label is not present, refer to an emissions control application guide. #### Regulation .02 Catalytic Converter. *COMAR 11.14.06.02* A. Most 1975 and newer passenger cars and 1975 through 1978 light-duty trucks with a manufacturer's GVW of 6,000 pounds or less were originally equipped with a catalytic converter. Some passenger cars were not originally equipped with a converter until later model years, and 1979 and newer light-duty trucks with a manufacturer's GVW of 8,501 pounds or more may not have been originally equipped with a catalytic converter. B. U.S. Environmental Protection Agency Program for Converter Replacement. (1) If a vehicle is less than 5 model years old and has been driven less than 50,000 miles, any catalytic converter shall be replaced with OEM equipment. (2) If a vehicle is more than 5 model years old or has been driven more than 50,000 miles, an EPA-approved new after market catalytic converter designed for the vehicle may be installed on the vehicle. An approved, reconditioned (used) catalytic converter may be installed provided the catalytic converter is an original type for the vehicle and has been certified by an EPA-approved testing facility. #### Regulation .03 Fuel Filler Inlet Restrictor (INRES). *COMAR 11.14.06.03* A. Vehicles originally equipped with a catalytic converter were also equipped with a fuel filler inlet restrictor to prevent the entry of a leaded fuel pump nozzle. B. Some later model light-duty trucks were not equipped with a catalytic converter but were equipped with a fuel filler inlet restrictor. The fuel filler inlet restrictor is required on these vehicles. #### Regulation .04 Positive Crankcase Ventilation System (PCV). *COMAR 11.14.06.04* A. All 1968 and newer passenger cars and 1968 through 1978 light-duty trucks with a manufacturer's GVW of 6,000 pounds or less, and 1979 and newer light-duty trucks with a manufacturer's GVW of 8,500 pounds or less are equipped with a crankcase ventilation system. B. Early model vehicles may be equipped with an open crankcase ventilation system where air is drawn in through the oil filler tube. Later model vehicles are equipped with a closed crankcase ventilation system where air is drawn in through the carburetor air cleaner. On this type system, the oil filler cap is sealed. #### Regulation .05 Air Injection System (AIS). *COMAR 11.14.06.05* A. Many 1968 and newer model vehicles are equipped with an air injection system which supplies air to the exhaust ports to extend the combustion process in the exhaust system. The system may be equipped with an external air pump. The pulse, aspirator, suction, or reed injection systems are not equipped with an air pump. Newer model vehicles may be equipped with an air pump which supplies air directly to the catalytic converter. #### Regulation .06 Exhaust Gas Recirculation System (EGR). *COMAR 11.14.06.06* A. Most 1973 and later model vehicles are equipped with an exhaust gas recirculation system to recirculate proper amounts of exhaust gases into the air/fuel mixture in the intake manifold. This recirculation into the manifold reduces combustion temperatures, thus reducing oxides of nitrogen (NOx). There are several types of EGR systems: a back pressure system which operates in conjunction with exhaust back pressure, a conventional system which operates on carburetor venturi vacuum, an electronically controlled system which operates from the engine computerized emissions control system, or a floor jet system which operates through jets in the floor of the intake manifold. #### Regulation .07 Evaporative Emissions System (EVP). *COMAR 11.14.06.07* A. Most 1971 and newer vehicles and some older models are equipped with an evaporative emissions system to collect and store gasoline vapors and gasoline from the carburetor and fuel system during engine operation or shut down. The vapors are collected and stored in a canister containing a charcoal filter and gasoline is returned to the fuel tank. The vapors are purged from the canister and drawn into the engine when the engine is started. A pressure vacuum gas cap is essential to the proper operation of this system.