Operation and maintenance manual

QSB4.5 and QSB6.7 Troubleshooting Symptoms Charts

Section TS - Troubleshooting Symptoms Page TS-3

Air Compressor Air Pressure Rises Slowly

Cause Correction

STEP 1

Air intake system restriction to air compressor is

excessive

.............

Replace the air compressor air cleaner (if

installed). Check the air intake piping. Check

engine air intake restriction if the air compressor

inlet is plumbed to the vehicle or equipment intake

system. Refer to Section 3 and Section 4.

Go To Next Step

STEP 2

Air system leaks

.............

Block the vehicle wheels and check the air system

for leaks with spring brakes applied and released.

Check for leaks from the air compressor gaskets

and the air system hoses, fittings, tanks, and

valves. Refer to the OEM service manuals.

Go To Next Step

STEP 3

Carbon buildup is excessive in the air discharge

line, downstream air valves, or cylinder head

.............

Check for carbon buildup. Replace the air

compressor discharge line and cylinder head

assembly if necessary. Refer to Section 7.

Go To Next Step

STEP 4

Contact a Cummins® Authorized Repair Facility