C9.3 Engines for Caterpillar Built Machines Engine Does Not Crank Caterpillar

Probable Causes

• Batteries

• Switches

• Starting Circuit

• Starting Motor or Flywheel Ring Gear

• Engine Accessories

• Internal Engine Problem

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the following procedures in the order that is provided.

Inspection of the Batteries and Battery Cables

1. Inspect the main power switch, battery posts, and battery cables for loose connections and for corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.

2. Inspect the batteries.

   1. Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".

   2. Load test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 V and 12 V Lead Acid Batteries".

Switches and/or Circuit Breakers (if applicable)

If equipped, check any switches and/or circuit breakers that may interfere with the engine cranking. Refer to the application electrical schematic for additional information.

Starting Motor Solenoid and Starting Circuit

Test the operation of the starting motor circuit. Refer to Systems Operation/Testing and Adjusting, "Electric Starting System" for additional information.

Inspect the Starter Pinion and Flywheel Ring Gear

1. Test the operation of the starting motor.

2. Check the pinion clearance. Inspect the pinion and the flywheel ring gear for damage. Refer to Systems Operation/Testing and Adjusting, "Electric Starting System" for additional information.

Inspect Engine Accessories and the Transmission (if applicable)

1. Ensure free movement of the driveline.

2. Remove any engine accessories that may lock up the engine and inspect any engine accessories that may lock up the engine.

   The following list illustrates examples of engine accessories that may lock up the engine:

   • Hydraulic pump that is driven from the rear gear group

   • Air compressor

   • Engine oil pump

   • Other components that are driven by the engine

Hydraulic Cylinder Lock

If an injector has been replaced, evacuate any fluids from the cylinder and attempt to start the engine. Fuel will flow from the cylinder head into the cylinders when a unit injector is removed.

If the engine will not start, check for fluid in the cylinders (hydraulic cylinder lock) by removing the individual unit injectors. Check for damaged seals. Determine the type of fluid that locked up the cylinder.

If there was a coolant leak, determine the cause of the leak.

If there was excessive fuel in the cylinder, replace the seals and reinstall the injector. Drain any excess fuel from the cylinder head.

If a mechanical problem is suspected, disassemble the engine. Refer to the Disassembly and Assembly manual. Inspect the internal components for the following conditions:

• Seizure

• Bent components

• Broken components