Usage:
BLACK OR GRAY
Engine Runs Smooth
Recommended Procedure
1. 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. See the RACK SETTING INFORMATION for the correct rack setting.
2. 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" (increase in speed) under load.
3. 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 at full load 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.
4. 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 with a clean air cleaner element.
5. Exhaust System Restriction Make a visual inspection of the exhaust system. Check for damage to piping or for a bad 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.
6. Fuel Injection Timing Not Correct Check and make necessary adjustments as per Testing and Adjusting section of the Service Manual.
7. Rack Setting Too High Check and make necessary adjustments as per Testing and Adjusting section of the Service Manual. See the RACK SETTING INFORMATION for the correct rack setting.
8. Low Quality Fuel Test the engine with fuel according to recommendations by the Caterpillar Tractor Co.
9. Valve Adjustment Not Correct or Valve Leakage Check and make necessary adjustments as per Testing and Adjusting section of the Service Manual. 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. Special Instruction (GMG00694) gives the test procedure.
10. Bad Fuel Nozzles Bad 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 as per Testing and Adjusting section of the Service Manual.
Engine Runs Rough
11. Misfiring Cylinders See the chart Misfiring and Running Rough.
12. Fuel Injection Timing Not Correct Check Check and make necessary adjustments as per Testing and Adjusting section of the Service Manual.
13. Automatic Timing Advance Does Not Operate Correctly Check with engine warm. Use the 1P3500 Timing Light Group. Special Instruction (SMHS6964) gives the test procedure. If the timing light is not available, make rapid "acceleration" (increase in speed) from low idle to high idle. 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 have exhaust noise (backfire) during acceleration. This condition is difficult to find if engine acceleration is slow or at a constant engine rpm.
14. Air in Fuel System With air in the fuel system the engine will normally be difficult to start, run rough and release a large amount of white smoke. Remove the air from the fuel system by either loosening the cap on the tee at the fuel filter, or by loosening the fuel line nuts one at a time at the cylinder heads. Turn the engine with the starter until the fuel flow at this connection is free of air. If air is not removed in this way, put 5 psi (0,35 kg/cm2) [CAUTION do not use more than 8 psi (0,56 kg/cm2)] of air pressure to the fuel tank and check for leaks at connections between the fuel tank and the fuel transfer pump. If there are no leaks at the connections, remove the supply line from the tank and connect it to an outside fuel supply. If this corrects the problem the suction line (standpipe) inside the fuel tank has a leak.