CAT D4G Loss of Power When Hot

[MikePhua]

A CAT D4G operator reported an issue where the machine loses power when the engine gets hot. The problem occurs during extended operation, where the engine starts to lose power as its temperature rises.
Initial Checks:

1. Cooling System Inspection: The first step was to check the cooling system, including the radiator and water pump. No issues were found in the cooling system; the radiator was working properly with no clogs or coolant issues.
   
2. Air Filter Check: The air filter was suspected to be a potential cause for the power loss. After inspection, it was determined that the air filter was not clogged, ruling out any airflow restrictions as the cause.
   
3. Fuel System Inspection: The fuel system was also inspected, including the fuel pump and filters. No obvious issues were found, and the fuel system was clear of blockages.
   

Further Investigation:

1. Electronic Control System: Next, the electronic control system, especially the engine control unit (ECU), was checked. No error codes were present, suggesting that the issue wasn't related to the ECU.
   
2. Temperature Sensors and Wiring: The temperature sensor wiring was inspected, and it was found that the wiring was worn and damaged, which affected the sensor's ability to read accurate data, leading to power loss when the engine heated up.
   
3. Exhaust System and Combustion Efficiency: The exhaust system was checked, focusing on exhaust temperature and pressure. High operating temperatures may lead to power loss if the exhaust system is clogged. After cleaning the exhaust system, power was restored.
   

Solution:

1. The worn temperature sensor wiring was replaced, and all connections to the electronic control system were verified.
   
2. The exhaust system was cleaned to ensure proper airflow and exhaust output.
   
3. Regular maintenance of the engine's cooling system was recommended, ensuring the radiator and water pump are functioning correctly.
   

Conclusion:
The CAT D4G was successfully fixed by replacing the damaged temperature sensor wiring and cleaning the exhaust system. The root cause of the issue was found to be the worn temperature sensor wiring, which caused incorrect readings and affected engine performance. By addressing these issues, the machine returned to normal operation, eliminating the overheating power loss problem.
For anyone encountering similar issues, checking the temperature sensors, cooling system, and exhaust system is a good place to start in order to identify and resolve the problem.