Cummins N14 STC, Celect, Celect Plus – Service Manual Smoke, Black – Excessive (PT)

Intake manifold pressure (boost) is below specification

Refer to the Intake Manifold Pressure (Boost) is Below Normal troubleshooting symptom tree in Section TS.

Air intake or exhaust leaks

Inspect the air intake and exhaust systems for air leaks. Refer to Procedure 010-024 in Section 10.

Fuel drain line restriction

Check or replace the fuel lines, check valves, or tank vents as needed. Refer to Procedure 006-012 in Section 6.

Air intake system restriction

Check the air intake system for restriction. Refer to Procedure 010-031 in Section 10.

Exhaust system restriction

Check the exhaust system for restrictions. Refer to Procedure 011-009 in Section 11.

Fuel grade is not correct for the application or the fuel quality is poor

Operate the engine from a tank of known high quality fuel. Refer to Fuels for Cummins® Engines, Bulletin 3379001.

PT fuel pump rated or no-air fuel pressure is above specification

Remove the fuel pump and check the calibration. Refer to Procedure 005-016 in Section 5 and the PT™ Fuel Pump Rebuild and Calibration Instructions, Bulletin 3379084.

Fuel rate and fuel pressure are high and intake manifold pressure is okay

Remove the fuel pump and check the calibration. Refer to Procedure 005-016 in Section 5 and the PT™ Fuel Pump Rebuild and Calibration Instructions, Bulletin 3379084.

Fuel rate is high, fuel pressure is okay or low, and intake manifold pressure is okay

Remove the injectors and check the calibration. Refer to Procedure 006-026 in Section 6.

Turbocharger wheel clearance is out of specification

Check the radial bearing and axial clearances. Inspect the turbocharger. Repair or replace the turbocharger, if necessary. Refer to Procedure 010-038 and Procedure 010-047 in Section 10.

Overhead adjustments are not correct

Measure and adjust the overhead settings. Refer to Procedure 003-004 in Section 3.

Injector cup is damaged or is not correct

Check the injector cups for damage and for correct part numbers. Refer to Procedure 006-026 in Section 6.

Turbocharger oil seal is leaking

Check the turbocharger compressor and turbine seals. Refer to Procedure 010-040 and Procedure 010-049 in Section 10.