N14 Base Engine Troubleshooting and Repair Manual – Engine Will Not Crank or Cranks Slowly (Air Starter)

Symptom Tree  t077

This is symptom tree t077
Cause Correction

Air pressure is low in the air tanks

Increase air pressure with an external air source. Refer to the OEM service manual.


Engine-driven units are engaged

Disengage engine-driven units.


Lubricating oil temperature is below specification the OEM service manual

Install an oil pan heater, or drain the oil and fill the system with warm oil.


Lubricating oil does not meet specifications for operating conditions

Change the oil and filters. Refer to Procedure 007-013.


Crankshaft rotation is impaired

Check the crankshaft for ease of rotation. Refer to Procedure 001-016.


Starting motor is malfunctioning or starting motor is not correct

Check the starting motor operation. Compare the starting motor with the engine and vehicle specifications. Refer to the manufacturer’s instructions.


Starting motor pinion or ring gear is damaged

Remove the starting motor, and inspect the gear. Refer to Procedure 013-020 and the manufacturer’s instructions.


Hot stall (hot start) in engine

Engine is hot and experiencing vapor lock. Refer to the OEM service manual.


Hydraulic lock in a cylinder

Remove the injectors and rotate the crankshaft. Look for the source of fluid in the cylinder. Refer to Procedures 006-026 and 001-016.


Internal engine damage

Analyze the oil and inspect the filters to locate an area of probable damage. Refer to Procedure 007-083.

Last Modified:  29-Mar-2005