3406E and 3456 Generator Set Engines Caterpillar

Probable Causes

• Emergency stop switch

• Engine Control Switch (ECS)

• Batteries

• Battery cables

• Starting circuit

• Starting motor solenoid

• Starting motor

• Flywheel ring gear

• Transmission

• Engine accessories

• Hydraulic cylinder lock

• Internal engine problem

Recommended Actions

Emergency Stop Switch

Verify that the emergency stop switch is in the OFF (out) position. If the switch is depressed, fuel injection is disabled and the engine will not crank. Refer to Troubleshooting, "Emergency Stop Switch Circuit - Test".

Engine Control Switch

1. Verify that the ECS is in the proper mode in order for the engine to start. Refer to Troubleshooting, "Engine Control Switch (ECS) Circuit - Test".

Batteries and/or 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 and 12 Volt Lead Acid Batteries".

Starting Motor Solenoid or Starting Circuit

1. Test the operation of the starting motor solenoid.

2. Check the wiring to the starting motor solenoid. Refer to troubleshooting, "Start Relay Circuit - Test".

Starting Motor or Flywheel Ring Gear

1. Test the operation of the starting motor.

2. Inspect the starter motor pinion and the flywheel ring gear for damage.

Engine Accessories

1. Ensure that the timing pin was not left in the flywheel housing.

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:

   • Fuel transfer pump

   • Air compressor

   • Engine oil pump

Hydraulic Cylinder Lock

Check for fluid in the cylinders (hydraulic cylinder lock) by removing the individual unit injectors.

Note: Drain the fuel from the cylinder head. Fuel will flow from the cylinder head into the cylinders when the unit injector is removed.

Internal Engine Problem

1. Disassemble the engine. Refer to Disassembly and Assembly.

2. Inspect the internal components for the following conditions:

   • Seizure

   • Broken components

   • Bent components