(1) Before beginning the test, the tester shall verify all of the following:

(a) The engine is within its normal operating temperature range;

(b) All vehicle accessories including air conditioning are off;

(c) The parking brake and an engine brake or retarder is off; and

(d) The transmission is in neutral (and clutch released if manual transmission).

(2) During the snap-acceleration test the tester shall do all of the following:

(a) Perform at least three preliminary snap-accelerations until the engine achieves consistent operation.

(i) A snap-acceleration consists of moving the accelerator pedal from normal idle as rapidly as possible to the full power position, then fully releasing the throttle so the engine returns to idle. Allow the engine to remain at idle for at least ten seconds between snap-accelerations.

(ii) Insert the opacity meter into an exhaust pipe.

(b) Perform additional snap-accelerations while measuring the smoke opacity.

(i) The tester must either begin a subsequent snap-acceleration within forty-five seconds or restart the test without removing the opacity meter.

(ii) The tester need not repeat the three preliminary snap-accelerations.

(c) Perform snap-accelerations (up to nine times if necessary) to obtain three consecutive peak opacity readings that meet ecology's standards. If this does not occur, the vehicle fails the test. Record the three final opacity readings.

(d) If the vehicle passes the first series of snap-accelerations, repeat these procedures for each additional exhaust pipe.

(3) Ecology may require variations to the testing procedures to accommodate the design of certain vehicles.