CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 86—CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES > SUBPART O—Emission Regulations for New Gasoline-Fueled Otto-Cycle Light-Duty Vehicles and New Gasoline-Fueled Otto-Cycle Light-Duty Trucks; Certification Short Test Procedures (§86.1401 to > 86.1434—Equipment preparation.

86.1434—Equipment preparation.

(a) Immediately prior to the wait time portion of the test run described in § 86.1437 or § 86.1438, or immediately prior to warmup operation, the steps described in paragraphs (b) through (d) of this section must be performed.
(b) Check the device(s) for removing water from the exhaust sample and the sample filter(s). Remove any water from the water trap(s). Clean and replace the filter(s) as necessary.
(c) Set the zero and span points of the analyzer with the electrical spanning network or with analytical gases.
(d) Attach the tachometer to the vehicle in accordance with the analyzer manufacturer's instructions. The manufacturer must ensure, for all test and production vehicles and engines, that the rpm signal is capable of being read by an exhaust gas analyzer via:
(1) A conventional inductive tachometer; or
(2) The onboard diagnostics (OBD) connector, as described under the provisions of § 86.094-17; or
(3) A dedicated electrical lead, marked “rpm” and located under the hood, with a female-type, quarter-inch spade terminal. The digital transistor-transistor logic (TTL) signal must span the 0V-5V range at a rate of one pulse per engine revolution, synchronized to the top dead center position.