Cummins N14 STC, Celect, Celect Plus – Service Manual Air Compressor Will Not Pump Air

Air governor is malfunctioning or not set correctly

Perform an exhaust gas analysis check. If the exhaust gases are not within specifications, perform the Starting Procedure for New Engine or Changed Conditions. Refer to Procedure 012-017 in Section 12.

Unloader valve is malfunctioning

Check the unloader valve and unloader body seal. Refer to Procedure 012-013 in Section 12.

Air compressor inlet restriction upstream

Inspect the air compressor head assembly and replace, if necessary. Refer to Procedure 012-103, Procedure 012-104, or Procedure 012-106 in Section 12.

Air compressor is excessively worn or internally damaged

Replace or rebuild the air compressor. Refer to Procedure 012-014 in Section 12 and the Holset® Air Compressors Master Repair Manual, Bulletin 3666121.

Cover gasket is ruptured (Holset® SS models only)

Check the discharge line for blockage. Refer to Procedure 012-103, Procedure 012-104, or Procedure 012-106 in Section 12. Check the cover gasket for flatness. Replace the cover gasket.

Splined drive coupling or gear is excessively worn

Check the coupling for wear. Refer to Procedure 012-014 in Section 12.