Section 1045.501 - How do I run a valid emission test?(a)Applicability. This subpart is addressed to you as a manufacturer but it applies equally to anyone who does testing for you, and to us when we perform testing to determine if your engines meet emission standards.(b)General requirements. Use the equipment and procedures for spark-ignition engines in 40 CFR part 1065 to determine whether engines meet the duty-cycle emission standards in §§ 1045.103 and 1045.105 . Measure the emissions of all exhaust constituents subject to emissions standards as specified in 40 CFR part 1065 . Measure CO2, N2O, and CH4 as described in § 1045.235 . Use the applicable duty cycles specified in § 1045.505 . Section 1045.515 describes the supplemental procedures for evaluating whether engines meet the not-to-exceed emission standards in § 1045.107 .(c)Fuels. Use the fuels and lubricants specified in 40 CFR part 1065, subpart H, for all the testing we require in this part, except as specified in § 1045.515 . (1) Use gasoline meeting the specifications described in 40 CFR 1065.710(c) for general testing. For service accumulation, use the test fuel or any commercially available fuel that is representative of the fuel that in-use engines will use.(2) You may alternatively use ethanol-blended fuel meeting the specifications described in 40 CFR 1065.710(b) for general testing without our advance approval. If you use the ethanol-blended fuel for certifying a given engine family, you may also use it for production-line testing or any other testing you perform for that engine family under this part. If you use the ethanol-blended fuel for certifying a given engine family, we may use the ethanol-blended fuel or the specified neat gasoline test fuel with that engine family.(d)Laboratory conditions. Ambient conditions for duty-cycle testing must be within ranges specified in 40 CFR 1065.520 , subject to the provisions of § 1045.115(d) . Emissions may not be corrected for the effects of test temperature or pressure. Humidity levels must represent actual in-use humidity levels; however, you may correct emissions for humidity as specified in 40 CFR 1065.670 .(e)Engine stabilization. Instead of the provisions of 40 CFR 1065.405 , you may consider emission levels stable without measurement after 12 hours of engine operation.(f)Maximum test speed. Instead of the provisions of 40 CFR 1065.510(f) , you may declare a value of maximum test speed for laboratory testing that is within 500 rpm of the corresponding measured value for maximum test speed.(g)Special and alternate procedures. If you are unable to run the duty cycle specified in this part for your engine (such as with constant-speed engines), use an alternate test cycle that will result in a cycle-weighted emission measurement equivalent to the expected average in-use emissions. This cycle must be approved under 40 CFR 1065.10 . You may use other special or alternate procedures to the extent we allow them under 40 CFR 1065.10 .(h)Laboratory testing with portable analyzers. You may use field-grade equipment for any laboratory testing with high-performance engines, as specified in 40 CFR 1065.901(b) , without requesting approval.73 FR 59194, Oct. 8, 2008, as amended at 74 FR 56510, Oct. 30, 2009; 86 FR 34514, June 29, 2021