New Jersey Administrative Code
Title 7 - ENVIRONMENTAL PROTECTION
Chapter 27B - SAMPLING AND ANALYTICAL PROCEDURES
Subchapter 4 - AIR TEST METHOD 4: TESTING PROCEDURES FOR DIESEL-POWERED MOTOR VEHICLES
Section 7:27B-4.3 - Procedures for using a smokemeter to measure the smoke opacity of heavy-duty diesel vehicles and diesel buses

1. Determine the engine horsepower from the engine identification plate or engine serial number. Refer to Table 1 below and input the nominal stack size into the smokemeter. If the engine identification plate is missing, inaccessible or illegible, measure the outside diameter of the exhaust pipe extending from the exhaust manifold with a precision caliper or equivalent gauge, rounding to the nearest inch;

2. For a PIF, only, affix the RPM sensor to the engine and vehicle according to the smokemeter manufacturer's instructions;

3. For a PIF, only, connect the engine RPM sensor to the smokemeter according to the smokemeter manufacturer's instructions;

4. Affix the smokemeter according to the manufacturer's instructions to the end of the vehicle's exhaust pipe. For full-flow smokemeters, ensure that the final two feet and the exit of the exhaust pipe is straight, with an internal diameter not to exceed five inches. Appropriate exhaust pipe adapters shall be used as necessary to comply with these specifications. Do not use full-flow smokemeters on vehicles with underbody exhaust pipes which direct the exhaust flow to the ground unless the exhaust gases are redirected away from the ground by the appropriate exhaust pipe adaptor mentioned above;

5. Chock the drive-wheels and release all tractor and trailer brakes;

6. Ensure that the transmission is in neutral and start the engine;

7. Ensure that the smokemeter is warmed up and calibrated according to N.J.A.C. 7:27B-4.2 and the manufacturer's instructions;

8. Initiate the test sequence on the smokemeter;

9. If using a partial-flow smokemeter, select the appropriate smoke opacity pass/fail standards, set forth at N.J.A.C. 7:27-14.6, based upon the engine model year. If using a full-flow smokemeter, enter the engine horsepower and stack diameter as measured from the vehicle exhaust stack;

10. If using a smokemeter without horsepower input, select the appropriate stack size from Table 1 below, based upon the vehicle's engine horsepower;

11. With each prompt from the smokemeter to "accelerate engine," rapidly depress the accelerator pedal to the floor and hold it there until prompted by the smokemeter to release the pedal;

12. Repeat (a)11 above at least four more times. This shall include, at a minimum, two preliminary snap accelerations to remove loose soot from the exhaust system for a stabilized reading, and a minimum of three snap accelerations for the official test, the average of which shall constitute the final test result; and

13. The pass/fail determination shall be based upon three valid smoke opacity test results averaged arithmetically and compared to the pass/fail standards appropriate for the engine model year.

+Note: Nominal stack size shall always be used when measuring engine smoke opacity, irrespective of the stack size equipped on the vehicle being tested. For example, a vehicle equipped with an engine rated at 301 horsepower or above which has an exhaust stack measuring seven inches in diameter shall, for purposes of an official test, have a nominal stack size of five inches input to the smokemeter. If, for example, a vehicle has no engine identification plate and is equipped with an exhaust stack measuring six or seven inches in diameter--but the exhaust pipe from the manifold is five inches in diameter--then the nominal stack size shall be five inches.

1. Determine the engine horsepower from the engine identification plate or engine serial number. Refer to Table 1 below and input the nominal stack size into the smokemeter. If the engine identification plate is missing, inaccessible or illegible, measure the outside diameter of the exhaust pipe extending from the exhaust manifold with a precision caliper or equivalent gauge, rounding to the nearest inch;

2. For a DEIC, only, affix the RPM sensor to the engine and vehicle according to the smokemeter manufacturer's instructions;

3. For a DEIC, only, insert the engine oil temperature sensor into the oil dipstick tube and into the crankcase oil according to the smokemeter manufacturer's instructions;

4. For a DEIC, only, connect the engine RPM and oil temperature sensors to the smokemeter according to the smokemeter manufacturer's instructions;

5. Affix the smokemeter according to the manufacturer's instructions to the end of the vehicle's exhaust pipe. For full-flow smokemeters, ensure that the final two feet and the exit of the exhaust pipe is straight, with an internal diameter not to exceed five inches. Appropriate exhaust pipe adapters shall be used as necessary to comply with these specifications. Do not use full-flow smokemeters on vehicles with underbody exhaust pipes which direct the exhaust flow to the ground unless the exhaust gases are redirected away from the ground by the appropriate exhaust pipe adaptor mentioned above;

6. Ensure that the smokemeter is warmed up and calibrated according to N.J.A.C. 7:27B-4.2 and the manufacturer's instructions;

7. Start the engine and operate at curb idle speed;

8. Purge the exhaust system of loose soot and stabilize the smoke opacity readings. For vehicles with 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. For vehicles with 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. The rolling acceleration portion of the test sequence shall be deemed to be complete as soon as:

9. Initiate the test sequence on the smokemeter;

10. Select the appropriate smoke opacity pass/fail standards from N.J.A.C. 7:27-14.6, based upon the engine model year;

11. 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;

12. If using a smokemeter without horsepower input, select the appropriate stack size from Table 1 below, based upon the vehicle's engine horsepower;

13. When testing a vehicle with a manual transmission, depress the clutch and select the appropriate low gear for the degree to which the vehicle is laden to avoid overgearing or lugging. When testing a vehicle with an automatic transmission, place the transmission in "D" or "Drive" only, or the gear position immediately next to "N" or "Neutral";

14. When testing a vehicle with a manual transmission, gradually engage the clutch;

15. 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;

16. When testing a vehicle with a low speed diesel engine, rapidly depress the accelerator pedal to the floor and hold for approximately three to five seconds or until prompted by the smokemeter to release the accelerator. When testing a vehicle with a medium or high speed diesel engine, rapidly depress the accelerator pedal to the floor and hold it there until an engine RPM of approximately 2,500 RPM is achieved, then release the accelerator pedal. When testing a vehicle with a manual transmission, do not shift to the next gear. The rolling acceleration portion of the test sequence shall be deemed to be complete as soon as:

17. Release the accelerator pedal, disengage the clutch and bring the vehicle to a stop; and

18. Determine whether the vehicle has passed or failed by comparing the smoke opacity test result to the standards set forth at N.J.A.C. 7:27-14.6 appropriate for the test vehicle's engine model year.

1. Unless the vehicle engine is of a torque-tube design, inspect the vehicle's drive shaft, U-joints and slip-joints for mechanical integrity. Discontinue testing of any vehicle exhibiting signs of appreciable looseness or wear in the U-joints or slip-joints, or any damage to the drive shaft which would adversely affect the vehicle's mechanical integrity. Do not resume testing unless and until the defects are repaired;

2. Ensure that the parking and service brakes are in good operating condition. Discontinue testing of any vehicle exhibiting inoperable or inadequate parking or service brakes. Do not resume testing unless and until the defects are repaired;

3. Determine the engine horsepower from the engine identification plate or engine serial number. Refer to Table 1 below and input the nominal stack size into the smokemeter. If the engine identification plate is missing, inaccessible or illegible, measure the outside diameter of the exhaust pipe extending from the exhaust manifold with a precision caliper or equivalent gauge, rounding to the nearest inch;

4. For a DEIC, only, affix the RPM sensor to the engine and vehicle according to the smokemeter manufacturer's instructions;

5. For a DEIC, only, insert the engine oil temperature sensor into the oil dipstick tube and into the crankcase oil according to the smokemeter manufacturer's instructions;

6. For a DEIC, only, connect the engine RPM and oil temperature sensors to the smokemeter according to the smokemeter manufacturer's instructions;

7. Affix the smokemeter according to the manufacturer's instructions to the end of the vehicle's exhaust pipe. For full-flow smokemeters, ensure that the final two feet and the exit of the exhaust pipe is straight, with an internal diameter not to exceed five inches. Appropriate exhaust pipe adapters shall be used as necessary to comply with these specifications. Do not use full-flow smokemeters on vehicles with underbody exhaust pipes which direct the exhaust flow to the ground unless the exhaust gases are redirected away from the ground by the appropriate exhaust pipe adaptor mentioned above;

8. Ensure that the smokemeter is warmed up and calibrated according to N.J.A.C. 7:27B-4.2 and the manufacturer's instructions;

9. Chock the drive-wheels;

10. Set the vehicle's parking brake;

11. Start the engine and operate at curb idle speed;

12. Purge the exhaust system of loose soot and stabilize the smoke opacity readings. Conduct at least three snap accelerations by rapidly depressing the accelerator pedal to the floor and holding until the engine speed reaches high idle or 2,500 RPM, whichever is lower before releasing, with five to 45 seconds between accelerations;

13. Initiate the test sequence on the smokemeter. Some smokemeters may not have a testing sequence entitled "power brake acceleration test." For these smokemeters, the snap acceleration test sequence may be used;

14. Select the appropriate smoke opacity pass/fail standard set forth at N.J.A.C. 7:27-14.6, based upon the engine model year;

15. 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 the actual stack diameter as measured upon the vehicle exhaust stack outlet;

16. If using a smokemeter without horsepower input, select the appropriate stack size from Table 1 below, based upon the vehicle's engine horsepower;

17. Apply the service brakes with the left foot;

18. Place the transmission in "D" or "Drive" or the gear position immediately next to "N" or "Neutral." Do not use the "LO" or "1" gear positions;

19. Rapidly depress the accelerator pedal to the floor and hold it there for approximately three seconds or until prompted to release it by the smokemeter;

20. Repeat (c)19 above at least two more times for a minimum total of three accelerations, with a pause of between five and 10 seconds between accelerations or until prompted by the smokemeter;

21. Three valid power brake accelerations shall constitute a successful test procedure and terminates the test;

22. Determine whether the vehicle has passed or failed based upon three valid smoke opacity test results averaged arithmetically and compared to the standards set forth at N.J.A.C. 7:27-14.6 appropriate for the test vehicle's engine model year; and

23. If the tests results are invalid and testing must be repeated, allow a minimum of three minutes but no more than five minutes of idling to cool the transmission before repeating the test.

+Note: Nominal stack size shall always be used when measuring engine smoke opacity, irrespective of the stack size equipped on the vehicle being tested. For example, a vehicle equipped with an engine rated at 301 horsepower or above which has an exhaust stack measuring seven inches in diameter shall, for purposes of an official test, have a nominal stack size of five inches input to the smokemeter. If, for example, a vehicle has no engine identification plate and is equipped with an exhaust stack measuring six or seven inches in diameter--but the exhaust pipe from the manifold is five inches in diameter--then the nominal stack size shall be five inches.