C9.3 Marine Auxiliary and Generator Set Engine Caterpillar

Engine Stalls at Low RPM

Usage:

C9.3 C93

Note: Refer to Troubleshooting, "Cat ET Service Features" for information about service features.

Probable Causes

Active codes and logged codes
Incorrect parameters
Low-pressure fuel system
Fuel injectors
Engine accessories
Parasitic loads

Recommended Actions

Complete the procedure in the order in which the steps are listed.

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Table 1
Troubleshooting Test Steps	Values	Results
1. Active Codes and Logged Codes A. Establish communication between Caterpillar^® Electronic Technician (Cat ET) and the Electronic Control Module (ECM) . Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Determine if a code is active or logged.	Diagnostic Code	Result: A code is not active or logged. Proceed to Test Step 2. Result: A code is active or logged. Repair: Troubleshoot any active codes before continuing with this procedure. If the problem is not resolved, proceed to Test Step 2.
2. Incorrect Parameters A. Use Cat ET to verify that the correct parameters are being used. Refer to Troubleshooting, "Configuration Parameters" for additional information.	Parameters	Result: The correct parameters are being used. Proceed to Test Step 3. Result: The correct parameters are not being used. Configure the correct parameters. If the problem is not resolved, proceed to Test Step 3.
3. Low Pressure Fuel System A. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. B. Ensure that the fuel supply valve (if equipped) is in the full OPEN position. C. Inspect the fuel system. Refer to Systems Operation/Testing and Adjusting, "Fuel System - Inspect" for additional information. Cold weather adversely affects the characteristics of the fuel. Refer to the engines Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold-weather operation. D. Check fuel quality. Check the fuel tank for debris or foreign objects which may block the fuel supply. E. Check the filtered fuel pressure while the engine is being cranked. Refer to Troubleshooting, "Fuel Pressure Is Low" for the proper testing procedure.	Fuel System	Result: The fuel system is operating properly. Proceed to Test Step 4. Result: The fuel system is not operating properly. Repair: Make the necessary repairs. Verify that the repair eliminates the problem. If the problem is not resolved, proceed to Test Step 4.
4. Fuel Injectors A. Use Cat ET to ensure that there are not any active diagnostic codes for the injector solenoids. Perform the "Cylinder Cutout Test" in order to check for a misfiring cylinder. Refer to Troubleshooting, "Injector Solenoid - Test" for information that is related to the test. Use Cat ET to perform the "Fuel System Verification Test" in order to check the mechanical condition of the fuel injectors. Refer to Troubleshooting, "Injector Solenoid - Test" for information that is related to the test.	Injector Solenoid Test or Fuel System Verification Test	Result: The test was successful. Proceed to Test Step 6. Result: The test was not successful. Repair: Diagnose the problem and then repair the problem. Reset all active codes and clear all logged codes. Verify that the repair eliminated the problem. If the problem is not resolved, proceed to Test Step 5.
5. Engine Accessories A. Inspect any engine accessories and the transmission (if applicable).	Engine Accessories	Result: An engine accessory is creating an excessive load. Repair: Repair the engine accessory. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).