Usage:
Black Or Gray Engine Runs Smooth
Engine Used at an Altitude Higher Than 2500 ft. (762 m)...At altitudes higher than 2500 ft. (762 m) the rack setting must be changed on 1145, 1150, and 1160 Engines to keep the smoke at a correct level. *
Engine Used in a Lug Condition..."Lugging" (when the truck is used in a gear too high for engine rpm to go up as accelerator pedal is pushed farther down, or when the truck is used in a gear where engine rpm goes down with accelerator pedal at maximum travel) the engine causes a reduction in the intake of air with full fuel delivery to the cylinders. Because there is not enough air to burn all the fuel, the fuel that is not used comes out the exhaust as black smoke. To prevent lugging the engine, use a gear where engine can have acceleration under load.
Dirty Air Cleaner...If the air cleaner has a restriction indicator, see if the red piston is in view. If there is no restriction indicator, restriction can be checked with a water manometer or a vacuum gauge (which measures in inches of water). Make the connection to the engine side of the air cleaner or to the engine inlet manifold. Check with the engine running a high idle rpm. Maximum restriction is 25 in. (635 mm) of water. If a gauge is not available, visually check the air cleaner element for dirt. If the element is dirty, clean the element or install a new element.
Air Inlet Piping Damage or Restriction... Make a visual inspection of the air inlet system and check for damage to piping, rags in the inlet piping, or damage to the rain cap or the cap pushed too far on the inlet pipe. If no damage is seen, check inlet restriction and replace clean air cleaner element.
Exhaust System Restriction...Make a visual inspection of the exhaust system. Check for damage to piping or for a defective muffler. If no damage is found, check the system by removing the exhaust pipes from the exhaust manifolds. With the exhaust pipes removed, start and run the engine to see if the problem is corrected.
Fuel Injection Timing Not Correct. *
Rack Setting Too High. *
Low Quality Fuel...Test the engine with fuel according to recommendations. See FUEL SPECIFICATIONS.
Valve Adjustment Not Correct or Valve Leakage...Check and make necessary adjustments. Intake valve adjustment is .015 in. (0,38 mm) and exhaust valve adjustment is .025 in. (0,64 mm). Valve leakage normally causes the engine to "misfire" (ignition not regular) and run rough. Valve leakage can be checked using the cylinder leakage tester. *
Defective Fuel Nozzles...Defective fuel nozzles will normally cause the engine to "misfire" (ignition not regular) and run rough, but can cause too much smoke with engine still running smooth. Remove the fuel nozzles and test.
Engine Runs Rough
Misfiring Cylinders...See the topic MISFIRING AND RUNNING ROUGH.
Fuel Injection Timing Not Correct. *
Automatic Timing Advance Does Not Operate Correctly...Engine must have smooth acceleration. A timing advance that does not operate correctly can cause delays of the engine acceleration at some rpm before high idle, or possibly cause the engine to run rough and backfire during acceleration. This condition is difficult to find if engine acceleration is slow or at a constant engine rpm.
Air in Fuel System...Prime the fuel system. See PRIMING THE FUEL SYSTEM.
White Smoke
Cold Outside Temperatures...When the air outside is cold, the cylinder temperature is cooler. Not all the fuel will burn in the cylinders. The fuel which does not burn comes out the exhaust as white smoke. White smoke is normal in cold temperatures until the engine operates long enough to become warm. There will be less white smoke if No. 1D diesel fuel is used.
Long Idle Periods...When an engine runs at idle speed for a long period of time, the cylinders cool and all of the fuel does not burn. Do not idle an engine for a long period of time. Stop engine when not in use. If long idle periods are necessary use No. 1D diesel fuel.
Low Quality Fuel...Test the engine with fuel according to recommendations. See FUEL SPECIFICATIONS.
Air in Fuel System ... See PRIMING THE SYSTEM.
Fuel Injection Timing Not Correct. *
Automatic Timing Advance Does Not Operate Correctly. *
Valve Adjustment Not Correct ... Check and make necessary adjustments. See VALVE LASH ADJUSTMENT.
Defective Fuel Nozzle(s) ... Defective fuel nozzles will normally cause the engine to "misfire" and run rough, and cause smoke. Replace the fuel nozzles. Fuel nozzles can be tested by your authorized dealer.
Misfiring Cylinder(s) ... See the topic MISFIRING AND RUNNING ROUGH.
Blue Smoke
Engine Oil Level Too High ... Do not overfill the crankcase. If the oil level in the crankcase goes up as the engine is used, check for fuel in the crankcase. See the topic FUEL IN CRANKCASE OIL.
Damage to Positive Crankcase Ventilator Valve or Valve Assembled Wrong. *
Worn Valve Guides. *
Worn Piston Rings and/or Cylinder Walls ... Worn piston rings and/or cylinder walls can be the cause of blue smoke and can cause a loss of compression. Check cylinder condition with the cylinder leakage tester. *
Wear or Damage to Pistons. *
*Authorized dealers are equipped with the necessary tools and personnel familiar with disassembly and assembly procedures to perform these services.