M11 Series – Service Manual – Engine Noise Excessive — Combustion Knocks

Symptom Tree  t048

This is symptom tree t048
Cause Correction

Refer to Engine Noise Diagnostic Procedures — General Information at the end of this section before using this symptom tree.

Engine is operating at low ambient temperature

Check the winterfront, shutters, and under-the-hood air. Use under-the-hood intake air in cold weather. Refer to Operation of Diesel Engines in Cold Climates, Bulletin 3379009.


Coolant temperature is below specification

Refer to the Coolant Temperature Below Normal symptom tree.


Ether starting aid is malfunctioning

Repair or replace the ether starting aids. Refer to the manufacturer’s instructions.


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 the Fuel for Cummins Engines, Bulletin 3379001.


Injector is malfunctioning

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


Overhead adjustments are not correct

Adjust the overhead settings. Refer to Procedure 003-004.

Last Modified:  05-Jan-2004