N14 Base Engine Troubleshooting and Repair Manual – Engine Runs Rough or Misfires

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Troubleshooting and Repair Manual CELECT™ Plus Systems, Bulletin 3666130, or Section TF of the CELECT™ Systems, Bulletin 3666084.

Injector is malfunctioning (CELECT™ and CELECT™ Plus)

Perform the automated cylinder performance test. Replace injectors as necessary. Refer to Procedures 006-005 and 006-026.

Injector is malfunctioning (PT/STC)

Remove and check the injectors. Replace injectors as necessary. Refer to Procedure 006-026.

Condition occurs only at idle

Refer to the Engine Runs Rough at Idle symptom tree.

Engine is operating at low ambient temperature

Check the shutters and engine compartment air. Refer to Operation of Diesel Engines in Cold Climates, Bulletin 3379009.

Electronic control module (ECM) calibration is malfunctioning

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history for applicable fixes to the calibration stored in the ECM. Refer to the calibration history spreadsheet Click here to see ecm_calibration_rev_history.xls

on QuickServe® Online Internet Website or the INCAL™ calibration CD. Compare the calibration stored in the ECM with the engine rating and the Control Parts List (CPL), Bulletin 4021326 or 4021327. If necessary, recalibrate the ECM. Refer to Procedure 019-032 in the Troubleshooting and Repair Manual for CELECT™ Plus Systems, Bulletin 3666130, or the Troubleshooting and Repair Manual for CELECT™ Systems, Bulletin 3666084.

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

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

Air in the fuel system

Check for air in the fuel system. Refer to Procedure 006-003.

Fuel inlet restriction

Check for fuel inlet restriction. Refer to Procedure 006-020.

Fuel pump pulsation damper is cracked

Inspect the fuel pump pulsation damper. Replace the pulsation damper if necessary. Refer to Procedure 005-031.

Overhead adjustments are not correct

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

Static injection timing is not correct

Check the static injection timing. Refer to Procedure 006-025.

Cylinder head valve leak

Check the cylinder head for fuel leaks between the valves and valve seats. Refer to Procedure 002-004.

Camshaft is damaged

Inspect the camshaft for damage. Refer to Procedure 001-008.

Internal engine damage

Analyze the oil and inspect the filters to locate an area of probable damage. Inspect for damaged crankshaft, pistons, and liners. Refer to Procedure 007-083.