INSERT 6T1263 - Caterpillar

Use this procedure in order to troubleshoot an overcrank condition for the engine, or use this procedure if the following diagnostic code is active. Refer to Troubleshooting, "Engine Monitoring Parameters" for information about engine events. Access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".
Table 1
Diagnostic Code    
Code and Description    Conditions which Activate the Code    System Response    
1664-31 Engine Automatic Start Failed     A starting attempt has exceeded the time that is programmed for the "Crank Duration" parameter.     The code is logged.
The red stop lamp is illuminated.
The engine is shut down. (1)    
( 1 ) Activation of this code latches an engine shutdown condition. The power to the ECM must be cycled prior to any additional attempts to start the engine.Probable Causes
Fuel supply
Electrical connectors or power supply
Engine speed/timing sensor
Ignition system
Incorrect base timing
Excessive loadRecommended Repairs
Fuel Supply
Ensure that fuel is supplied at a sufficient pressure that is stable. Ensure that the size of the fuel line is sufficient in order to provide the engine with the correct volume of fuel. Inspect the fuel system for leaks.The following conditions can cause a problem with the engine operation:
Low fuel pressure
High fuel pressure
Poor fuel qualityEnsure that the fuel pressure is correct. When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed.Inspect the fuel system components: fuel filter, gas pressure regulator, gas shutoff valve and fuel actuator. Verify that the system components are operating correctly.Replace the fuel filter, if necessary.Electrical Connectors or Power Supply
There may be an intermittent interruption of power. Check the wiring harnesses and the connectors. Inspect the connectors in the terminal box. Inspect the power supply connections and the ground.Inspect the wiring from the power supply to the ECM. Check the power and ground connections. Refer to Troubleshooting, "Electrical Power Supply - Test".Speed/Timing Sensor
Visually inspect the engine speed/timing sensor. Ensure that the sensor is installed correctly. Use Caterpillar Electronic Technician (ET) to check for a diagnostic code that is related to the engine speed/timing sensor. Refer to Troubleshooting, "Speed/Timing - Test".Ignition System
Inspect the ignition system for the following conditions:
Check the connections between the ignition transformers and the spark plug wires. A loose connection can cause arcing and misfires.
Check the connections between the spark plug wires and the spark plugs for a loose connection or for pin holes that are caused by arcing. Both conditions can cause misfires.
Check for corrosion on the terminal of the spark plug and check for wear on the electrode. Both conditions can cause misfires.Losses or misfires are caused by shorts or excessive moisture.Maintain the spark plug according to the Operation and Maintenance Manual.Check the Base Timing
Verify that the base timing is correct. Refer to Testing and Adjusting, "Ignition Timing - Adjust".Excessive Load
Ensure that the load is not excessive. Reduce the load.