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Virginia Administrative Code
Title 9. Environment
Agency 5. State Air Pollution Control Board
Chapter 91. Regulations for the Control of Motor Vehicle Emissions in the Northern Virginia Area
1/22/2021

9VAC5-91-440. Two-speed idle test procedure.

A. The emissions inspection procedure shall be a two-speed idle test as specified in section (II) of Appendix B of 40 CFR Part 51, Subpart S.

1. The two-speed idle test shall consist of a test of the vehicle's exhaust emissions at idle and at 2500 rpm while the vehicle's gear selector is in neutral or park.

2. The idle test shall be administered after the 2500 rpm test. The tests shall be run consecutively.

3. The complete test shall consist of a first chance 2500 RPM mode test; followed by a first chance idle mode test. If either first chance mode fails, the first chance shall be followed by a preconditioning at 2500 RPM for up to three minutes and a second chance 2500 RPM mode test followed by a second chance idle mode. The department may eliminate the need to repeat a mode that passed the first chance test.

4. If the vehicle fails the first chance test, the second chance test and preconditioning shall be omitted if no exhaust hydrocarbon concentration less than 1800 ppm is detected within an elapsed time of 30 seconds. The department may eliminate the need to do a second chance test if the vehicle has already failed an emissions component check.

5. Motor vehicle manufacturers and the Environmental Protection Agency may issue special test instructions for specific vehicle models which shall be followed in lieu of the test procedures specified in this section if such instructions are provided through the administrator.

6. In order to pass the two-speed idle test, the vehicle's exhaust shall not exceed the standards listed in 9VAC5-91-160.

7. Vehicles which are required to receive OBD testing shall be connected to the appropriate test equipment according to vehicle and analyzer manufacturer instructions. The OBD test shall be performed prior to the two-speed idle test.

B. The idle test mode shall be performed as follows:

1. The vehicle transmission shall be in neutral or park and the parking brake applied; the engine shall be operating at curb idle and there shall not be any manipulation of the engine throttle mechanism.

2. The engine speed (RPM) shall be obtained and shall be between 400 and 1250 RPM for the duration of the test mode.

3. The pass/fail analysis shall begin after an elapsed time of 10 seconds.

4. The idle mode elapsed time shall be 30 seconds.

5. The exhaust concentrations shall be measured as percent carbon monoxide and parts per million hydrocarbons after stabilized readings are obtained and averaged over the last five seconds at the end of the idle test mode.

C. The 2500 RPM test mode shall be performed as follows:

1. The vehicle transmission shall be in neutral or park.

2. The vehicle engine speed shall be increased from idle to between 2200 and 2800 RPM and maintained at that level.

3. If the engine speed varies outside the parameters of 2200 to 2800 RPM for more than two seconds during a sampling period, the 2500 RPM mode shall be invalid and the 2500 RPM test shall be restarted. If the engine speed varies outside such parameters for more than a cumulative total of 10 seconds, the 2500 RPM test mode shall be invalid and another initiated.

4. The pass/fail analysis shall begin after an elapsed time of 10 seconds.

5. The 2500 RPM mode elapsed time shall be 30 seconds.

6. The exhaust concentrations shall be measured as percent carbon monoxide and parts per million hydrocarbons after stabilized readings are obtained and averaged over the last five seconds at the end of the 2500 RPM test mode.

Statutory Authority

§ 46.2-1180 of the Code of Virginia; § 182 of the Clean Air Act; 40 CFR Part 51, Subpart S.

Historical Notes

Derived from Volume 13, Issue 05, eff. January 24, 1997; amended, Virginia Register Volume 18, Issue 20, eff. October 1, 2002; Volume 29, Issue 24, eff. August 28, 2013; Volume 35, Issue 05, eff. November 28, 2018.

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