PURPOSE: This rule requires proper maintenance of original emission control devices and systems on 1968 and subsequent year motor vehicles.

1. (1) Definitions of terms specified in this rule may be found in 10 CSR 10-6.020.

2. (2) Ignition System and Engine Speed. All 1968 and subsequent model year gasolinepowered motor vehicles shall be maintained so as to be in compliance with the following requirements:

   1. (A) The number of revolutions per minute of an engine while operating at idle speed shall be in accordance with the specifications and determined under conditions published by the manufacturer, but in no case shall the idle speed be less than the minimum specified in the manufacturer’s published specifications. Revolutions per minute shall be determined by a tachometer or other device which shall be tested for accuracy and precision at reasonable intervals under those terms and conditions as the staff director may direct;
   2. (B) Ignition timing of an engine shall comply with the published specifications of the manufacturer as determined in accordance with procedures and conditions specified by the manufacturer; and
   3. (C) All cylinders shall be firing.

3. (3) Crankcase Ventilation System. The positive crankcase ventilation system on all 1968 and subsequent model year gasoline-powered motor vehicles, except motorcycles and motor tricycles, and all 1969 and subsequent model year gasoline-powered motor vehicles, including motorcycles and motor tricycles, shall meet the following requirements:

   1. (A) The plumbing and connections shall be properly connected as installed by the manufacturer and free of obstructions and leakage;
   2. (B) There shall be a negative pressure (suction) at the inlet of the crankcase ventilation valve; and
   3. (C) The crankcase ventilation valve shall be freely operative so as to regulate the flow of gases through the system.

4. (4) Exhaust Emission Control Systems.

   1. (A) Air Injection Systems. Exhaust emission control air injection systems on those gasoline-powered motor vehicles so equipped by the manufacturer shall operate so that—

      1. 1. The air delivery hoses, connections

and air distribution manifold shall be properly connected as installed by the manufacturer and free of obstructions and leakage;

1. 2. The air compressor drive belt tension

shall be within manufacturer’s specification;

1. 3. There is a positive air flow from the

air pump to the air delivery distribution manifold;

1. 4. The check valve prevents any reverse

air flow from the air distribution manifold out through the check valve inlet; and

1. 5. The antibackfire valve, gulp-valve, air

bypass valve or other similar device with the same function permits the passage of air from the air pump to the exhaust manifold(s), except when the carburetor throttle is closed rapidly from an open position as in deceleration.

1. (B) Engine Modification Systems. All vacuum control valves, vacuum lines, mechanical linkage, electrical circuits and switches peculiar to certain engine modification systems shall be properly connected as installed on all 1968 and subsequent model year gasoline-powered motor vehicles so equipped by the manufacturer.

2. (C) The requirements of section (4) shall apply to all gasoline-powered motor vehicles with the following exceptions:

   1. 1. Vehicles of 1967 or earlier model

year;

1. 2. Vehicles not equipped by the manu-

facturer with exhaust emission control air injection systems;

1. 3. Commercial vehicles of over one

thousand pounds (1,000 lbs.) designed capacity; or

1. 4. Motor vehicles with an engine dis-

placement of less than fifty (50) cubic inches (819.35 cubic centimeters).

AUTHORITY: section 643.050, RSMo Supp. 1992.* Original rule filed April 26, 1968, effective May 6, 1968. Amended: Filed Aug. 16, 1977, effective Feb. 11, 1978. *Original authority: 643.050, RSMo 1965, amended 1972, 1992. Op. Atty. Gen. No. 331, Shell (11-15-71). The Missouri Air Conservation Commission does not have any specific authority to require the installation of emission monitoring devices, but does have the authority to require reports from sources of air pollution relating to rate, period of emission and composition of effluent, and to make such information available to the public, unless any such information is “confidential” as defined by section 203.050.4, RSMo 1969. 10 CSR 10-3