Operation and maintenance manual

Troubleshooting Symptoms Charts QSB4.5 and QSB6.7
Page TS-26 Section TS - Troubleshooting Symptoms
Engine Noise Excessive — Combustion Knocks
Cause Correction
STEP 1
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 Cold Weather Operation, see
Bulletin 3387266, and Section 1.
OK
Go To Next Step
STEP 2
Ether starting aid is malfunctioning
.............
Repair or replace the ether starting aids. Refer to
the manufacturer's instructions.
OK
Go To Next Step
STEP 3
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 Fuel Recommendations and
Specifications in Section V.
OK
Go To Next Step
STEP 4
Air in the fuel system
.............
Check for air in the fuel system. Tighten or replace
the fuel connections, fuel lines, fuel tank
standpipe, and fuel filters as necessary.
OK
Go To Next Step
STEP 5
Coolant temperature is below specification
.............
Refer to the Coolant Temperature Below Normal
symptom tree.
OK
Go To Next Step
STEP 6
Contact a Cummins® Authorized Repair Facility