Cummins N14 STC, Celect, Celect Plus – Service Manual Engine Decelerates Slowly (PT)

Throttle linkage or return spring is binding

Check the fuel pump throttle linkage and return spring for free movement. Adjust if necessary.Refer to the OEM service manual.

Fuel drain line restriction

Check or replace the fuel lines, check valves, or tank vents as needed. Refer to Procedure 006-012 in Section 6.

Fuel tank vents are plugged or damaged

Remove and clean the tank vents. Replace the vents, if necessary. Refer to the OEM service manual.

Overhead fuel tank check valve is restricted or is not opening

Check the fuel tank check valve for debris. Check the valve for the correct plumbing arrangement. Refer to the OEM service manual.

Fuel pump pulsation damper is cracked

Inspect the fuel pump pulsation damper. Replace the pulsation damper if necessary. Refer to Procedure 005-031 in Section 5.

PT fuel pump throttle leakage is excessive

Remove the fuel pump. Refer to the PT™ Fuel Pump Rebuild and Calibration Manual, Bulletin 3379084.

Injector check ball is not seating correctly or is missing

Check the injectors. Repair or replace the injectors as necessary. Refer to Procedure 006-026 in Section 6.

Injector is malfunctioning (PT/STC)

Remove and check the injectors. Replace injectors as necessary. Refer to Procedure 006-026 in Section 6.