ALTERNATOR GP -B 10R9790 - Caterpillar

Note: Use this procedure only if the engine shuts down completely and the engine must be restarted.Probable Causes
Active engine shutdown
Electrical connectors or power supply
Circuit breaker
Engine speed/timing signal
Fuel supply
Fuel quality
Spark plugRecommended Actions
Active Engine Shutdown
Use the Caterpillar Electronic Technician (ET) to check for any active engine shutdowns and/or logged engine shutdowns. Determine the reason for the shutdown. After correcting the problem, set the engine control to the OFF/RESET mode for at least 15 seconds before you try to restart the engine.Electrical Connectors or Power Supply
Check the wiring harnesses and the connectors. Inspect the connectors in each of the junction boxes. Inspect the power supply connections and the ground. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Use Cat ET to check for the 168-02 diagnostic code for erratic system voltage. If this diagnostic code is logged, proceed to Troubleshooting, "Electrical Power Supply - Test".
Inspect the wiring from the power supply to the power distribution box. Inspect the wiring from the power distribution box to the ECM. Check the power and ground connections at the ECM. Refer to Troubleshooting, "Electrical Power Supply - Test" for more information.Circuit Breakers
Check that the circuit breakers have not tripped. The circuit breaker may exceed the trip point due to overheating. Reset the circuit breaker if a circuit breaker is tripped.Engine Speed/Timing Signal
Loss of the signal from the engine speed/timing sensor will cause a shutdown. Use Cat ET to check for logged diagnostic codes. For more information, refer to Troubleshooting, "Speed/Timing - Test".Fuel Supply
Use Cat ET to check that the engine fuel parameters are correct for the fuel that is being used. If necessary, perform fuel analysis in order to confirm the fuel quality.Verify 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 has been changed.Ensure that fuel is supplied at a sufficient pressure that is stable. Check that the size of the fuel line is sufficient. Inspect the fuel system for leaks.The following conditions can affect engine starting:
Low fuel pressure
High fuel pressure
Poor fuel qualityInspect the following fuel system components:
Fuel filter
Gas pressure regulator
Gas shutoff valve
Fuel metering valveVerify that the system components are operating correctly.Repair suspect components. Replace the fuel filter, if necessary.Fuel Quality
Compare the Low Heat Value (LHV) of the gas supply to the "Fuel Quality" parameter that is programmed by the customer into the Electronic Control Module (ECM). The ECM uses the setting for start-up and for air/fuel ratio control at low loads.If the LHV of the fuel does not match the "Fuel Quality" parameter that is programmed into the ECM, program the correct setting for the "Fuel Quality" parameter.Spark Plug
An engine shutdown that is due to a faulty spark plug is likely to occur when the engine is operating under a load. Refer to Troubleshooting, "Ignition Secondary - Test".