GLASS-FRONT 4961130 - Caterpillar

Probable Causes
Electrical connectors
Diagnostic codes
Fuel quality
Fuel injectors
High-pressure fuel system
Throttle signal
Air inlet and exhaust system
Valve lash adjustmentRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Stop the engine. Remove electrical power from the Electronic Control Module (ECM).
B. Proceed to Troubleshooting, "Electrical Connectors - Inspect" for information related to checking for harness and connector problems.
Electrical connectors
and
wiring
Result: Harnesses and connectors appear to be OK.
Proceed to the next step
Result: There is a problem with the connectors and/or wiring.
Perform the necessary repairs to the connectors and/or wiring.
If the problem is not resolved, proceed to the next step.
2. Check the Fuel Quality
A. Obtain a fuel analysis in order to confirm that the fuel quality is OK for this engine.
Fuel quality
Result: The fuel quality is OK.
Proceed to the next step.
Result: The fuel quality is NOT OK.
Replace the fuel. Verify that the repair eliminated the problem.
If the problem is not resolved, proceed to the next step.
3. Check for Problems Associated with the Fuel Injection System
A. Check for diagnostic codes related to the fuel injection system.
1. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
2. Monitor the diagnostic codes on Cat ET. Check for an active diagnostic code related to an injector.
Note: Wait at least 30 seconds in order for diagnostic codes to become active.
B. Perform the "Injector Solenoid Test" to identify electrical problems in the fuel injection system.
C. Perform the "Cylinder Cutout Test" to locate misfiring cylinders.
Refer to Troubleshooting, "Injector Solenoid - Test" for procedural information.
Fuel injection system
Result: The fuel injection system is in good repair. There are no electrical problems or misfiring cylinders.
Proceed to the next step.
Result: An electrical problem or misfiring cylinder has been identified.
Perform the necessary repairs.
If the problem is not resolved, proceed to the next step.
4. Check the Pressure in the High Pressure Fuel System
A. Check that the fuel pressure in the high-pressure fuel system is correct. Refer to Troubleshooting, "Fuel Pressure Is Low" for the correct procedural information.
High pressure fuel system
Result: The high-pressure fuel system is producing the correct pressure.
Proceed to the next step.
Result: The high-pressure fuel system is not producing the correct pressure.
Troubleshoot the system in order to isolate the problem. Perform the necessary repairs.
If the problem is not resolved, proceed to the next step.
5. Verify that the Throttle Signal is Steady and Smooth
A. Monitor the status of "Throttle Position" on Cat ET. Check that the signal rises smoothly from low idle to high idle. Also, ensure that the signal holds steady through the entire range of the throttle.
Throttle position signal
Result: The throttle signal is smooth and steady throughout the range of the throttle.
Proceed to the next step.
Result: The throttle signal is not smooth and steady throughout the range of the throttle.
Troubleshoot and repair the throttle. Replace the throttle sensor, if necessary.
If the problem is not resolved, proceed to the next step.
6. Check the Air Inlet and Exhaust System for Problems
A. Check for an air filter restriction. Clean plugged air filters