C9.3 Engines for Caterpillar Built Machines Engine Stalls at Low RPM Caterpillar


Engine Stalls at Low RPM
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Probable Causes

  • Active codes and logged codes

  • Incorrect parameters

  • Air shut-off system

  • Low-pressure fuel system

  • Fuel injectors

  • Engine accessories

  • Parasitic loads

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

Table 1
Troubleshooting Test Steps  Values  Results 

1. Active Codes and Logged Codes

A. Establish communication between Cat® Electronic Technician (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 active or logged.

Repair: Troubleshoot any active codes before continuing with this procedure.

Result: A code is not active or logged.

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.
 

3. Air Shutoff System (if equipped)

A. Check for proper operation of the air shutoff system. Refer to Troubleshooting, "Air Shutoff - Test".
 

Air Shutoff
 

Result: The air shutoff is operating correctly.

Proceed to Test Step 4.

Result: The air shutoff is not operating correctly.

Repair: Make the necessary repairs. Verify the repair.
 

4. 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 5.

Result: The fuel system is not operating properly.

Repair: Make the necessary repairs. Verify that the repair eliminates the problem.
 

5. Fuel Injectors

C9.3 Applications

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.
 

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.
 

6. 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.
 

Information System:

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