68292 Force NUT (.312-18)

Recommended Actions
Table 1
Troubleshooting Test Steps Values Results
1. Engine Operation
A. Use Caterpillar Electronic Technician (ET) to check the "Current Totals" for excessive idle time and/or for a high load factor which would be indicative of poor operating habits.
Engine Operation
Result: Cat ET shows no sign of excessive idle time and/or high load factor.
Proceed to Test Step 2.
Result: Cat ET shows signs of excessive idle time and/or high load factor.
Repair: Make the necessary repairs and return to service.
2. Fuel Leaks
A. Check the fuel pressure during engine cranking.
B. Check the fuel pressure after the fuel filter.
Refer to the Systems Operation and Testing and Adjusting for the correct pressure values.
Fuel Leaks
Result: The fuel pressure during engine cranking and after the fuel filter is within specifications.
Proceed to Test Step 3.
Result: The fuel pressure during engine cranking and after the fuel filter is not within specifications.
Repair: If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items:
- Fuel Transfer Pump
- Fuel Transfer Pump Coupling
- Fuel Pressure Regulating Valve
3. Fuel Quality
A. Verify that the fuel quality is correct.
Note: Cold weather adversely affects the characteristics of the fuel.
Fuel Quality
Result: The fuel quality is correct.
Proceed to Test Step 4.
Result: The fuel quality is not correct.
Repair: Refer to the Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold-weather operation.
4. Engine Speed/Timing
A. Perform a speed/timing sensor calibration.
Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate" for troubleshooting information.
Timing Signal
Result: The speed/timing sensor is operating properly.
Proceed to Test Step 5.
Result: The speed/timing sensor is not operating properly.
Repair: Repair the speed/timing sensor.
Verify that the repair eliminated the problem.
5. Unit Injectors
A. Check for correct installation of the J1/P1 and J2/P2 Electronic Control Module (ECM) connectors and the unit injector connectors.
B. Perform the "Injector Solenoid Test" on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM.
C. Perform the "Cylinder Cutout Test" in order to identify any injectors that might be misfiring.
Refer to Troubleshooting, "Injector Solenoid - Test".
Fuel Injectors
Result: The connectors were correctly installed and the test were successful.
Proceed to Test Step 6.
Result: The connectors were not installed correctly and the test were not successful.
Repair: Reinstall the connectors correctly and remove the suspect injector, and install a new electronic unit injector. Refer to Disassembly and Assembly.
Ensure that the repairs have determined the problem.
6. Air Inlet and Exhaust System
A. Check the air filter restriction indicator, if equipped. Clean plugged air filter or replace plugged air filters. Refer to the Operation and Maintenance Manual.
B. Check the air inlet and exhaust system for restrictions and/or leaks.
Restrictions
Result: There are restrictions in the air inlet or exhaust system.
Repair: Make the necessary repairs. Verify that the repair eliminated the problem.
Result: There are no restrictions in the air inlet or exhaust system.
Proceed to Test Step 7.
7. Accessory Equipment
A. Check all accessory equipment for problems that may create excessive load on the engine.
Engine Accessories
Result: There is no engine accessories creating an excessive load on the engine.
STOP
Result: An engine accessory is creating an excessive load.
Repair: Repair the engine accessory.
Verify that the repair eliminated the problem.