3 1
Initiate the test sequence on the smokemeter.
Select the appropriate smoke opacity pass/fail standards, based upon the engine model year.
If using a partial-flow smokemeter, select the appropriate stack size from Table 1 below, based upon the
engine horsepower. If using a full-flow smokemeter, enter the engine horsepower and nominal stack size
as measured on the vehicle.
If using a smokemeter without horsepower input, select the appropriate stack size from Table 1 on page
34, based upon the vehicle’s engine horsepower.
Low speed diesel engines: conduct one rolling acceleration by rapidly depressing the accelerator pedal
to the floor and holding it there for three to five seconds, or until prompted by the smokemeter to release
the pedal.
Medium or high speed diesel engines: conduct three rolling accelerations by rapidly depressing the
accelerator pedal to the floor and briefly holding it there until the engine speed reaches approximately
2,500 RPM, then release. When testing a vehicle with a manual transmission, do not shift to the next
gear.
Manual transmissions:
depress the clutch and select the appropriate low gear for the degree to which
the vehicle is laden to avoid over-gearing or lugging. Gradually engage the clutch.
Automatic transmissions: place the transmission in “D” or “Drive” only, or the gear position immediately
next to “N” or “Neutral”. Accelerate until the vehicle is rolling forward at a speed equivalent to the engine
curb idle, then increase the engine speed by 200 RPM, ±50 RPM.
Release the accelerator pedal, disengage the clutch and bring the vehicle to a stop.