Cummins ISX11.9 CM2250 – Service Manual Air Compressor Air Pressure Rises Slowly

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 Procedure 012-019 in Section 12 and the OEM service manuals. Turn the keyswitch ON. Walk around the engine and listen for air leaks.

Carbon buildup is excessive in the air discharge line, check valve, or cylinder head

Check for carbon buildup. Replace the air compressor discharge line, cylinder head, or air compressor. Check the turbocharger for oil leaks. Check the intake tube for oil. Refer to and
Procedure 010-033 in Section 10 and Procedure 012-003 in Section 12.

Air system component is malfunctioning

Check the operation of the air system valves, air dryers, and other OEM-installed air system components. Refer to the OEM service manual. Check the operaton of the aftertreatment purge air actuator. Refer to Procedure 012-003 in Section 12.

Air intake system restriction to air compressor is excessive

Replace the air compressor air cleaner (if installed). Check the air intake piping. Check the engine air intake restriction if the air compressor inlet is plumbed to the vehicle or equipment intake system. Refer to Procedure 010-031 in Section 10.

Air compressor intake or exhaust system leaks air

Inspect the air compressor head assembly and replace, if required. Refer to Procedure 012-003 in Section 12.