Troubleshooting and Resolving Startup Issues with the CAT 955K

[MikePhua]

The CAT 955K is a highly regarded track loader that has earned its place as a reliable machine in construction, mining, and industrial sectors. However, even the most dependable machines can face startup issues, which can cause operational downtime and impact project timelines. If your CAT 955K won’t start, it can be frustrating, but understanding common causes and knowing how to troubleshoot effectively can save time and reduce the need for costly repairs.
In this article, we’ll explore the possible reasons why your CAT 955K won’t start, offer detailed troubleshooting steps, and share real-world examples of how others have successfully solved similar problems.
Understanding the CAT 955K: Key Features
Before we dive into troubleshooting, it’s important to understand the core features of the CAT 955K. This machine is equipped with a diesel engine and is designed for tough work environments, making it ideal for tasks such as material handling, grading, and excavation.

• Engine Type: Diesel engine, typically the CAT 3306 or CAT 3304.
  
• Horsepower: Approximately 130-150 HP.
  
• Transmission: Powershift transmission, which is essential for smooth operation during heavy-duty tasks.
  
• Hydraulics: Advanced hydraulic system for lifting and moving materials.
  

Given its mechanical complexity, any issues with starting can often be traced back to the engine or electrical systems.
Common Reasons Why the CAT 955K Won’t Start
The following are some of the most common issues that may cause a CAT 955K to fail to start:
1. Fuel System Issues
One of the most frequent causes of startup problems is a malfunction in the fuel system. Common issues can include:

• Clogged fuel filters: Over time, fuel filters can get clogged with dirt, debris, and other contaminants, preventing proper fuel flow to the engine.
  
• Air in the fuel system: If air enters the fuel lines, it can prevent the engine from receiving a sufficient fuel supply, leading to starting failure.
  
• Contaminated fuel: Water or debris in the fuel tank can prevent proper combustion and cause the engine to fail to start.
  

Solution: Start by inspecting and replacing the fuel filters. If air in the fuel lines is suspected, bleed the fuel system to remove trapped air. Make sure to drain any contaminated fuel and replace it with fresh, clean fuel.
Real-World Example: A contractor in Ohio faced starting issues with their CAT 955K after storing it for several months. Upon inspection, they found that the fuel was contaminated with water. After draining the fuel tank, replacing the filters, and refilling with fresh fuel, the machine started without any issues.
2. Battery and Electrical System Problems
The electrical system is another key area that can lead to a machine failing to start. Some common electrical issues include:

• Dead or weak battery: If the battery voltage is too low, the starter motor won’t be able to turn the engine over.
  
• Loose or corroded battery terminals: Loose connections or corrosion on the terminals can prevent the battery from delivering sufficient power to the starter motor.
  
• Faulty starter motor: Over time, the starter motor can wear out, preventing the engine from starting.
  

Solution: Begin by checking the battery voltage with a multimeter. If the voltage is below 12.5 volts, recharge or replace the battery. Clean the battery terminals and ensure they are tightly connected. If the battery is fine, test the starter motor by bypassing the ignition switch to see if it engages. A faulty starter may need to be replaced.
Real-World Example: A construction company in Florida had their CAT 955K refuse to start despite having a full fuel tank. After inspecting the electrical system, they found corrosion on the battery terminals. After cleaning the terminals and securing the connections, the machine started without issues.
3. Ignition Switch and Relay Problems
The ignition switch and associated relays control the starting sequence of the CAT 955K. If there is an issue with these components, the machine may not receive the correct signals to start. Symptoms can include:

• No response when turning the key: The starter motor does not engage when the key is turned, indicating a potential issue with the ignition switch.
  
• Clicking sounds: A clicking sound when turning the key could indicate a relay or starter solenoid issue.
  

Solution: First, check the ignition switch to ensure it’s functioning properly. If there’s no response when turning the key, the switch may need to be replaced. Test the relays by checking for continuity and replacing any faulty components.
Real-World Example: A mining operation in Nevada faced intermittent starting issues with their CAT 955K. After checking the relays, they discovered that a faulty ignition relay was the root cause. After replacing the relay, the machine started reliably without further issues.
4. Hydraulic System Problems
The hydraulic system in the CAT 955K can also cause issues with starting. If the system is under too much load, it can place excessive pressure on the engine, making it difficult to start. Common causes include:

• Hydraulic fluid leaks: Leaks in the hydraulic system can reduce the fluid level, leading to issues when trying to start the engine.
  
• Sticking hydraulic valves: If hydraulic valves stick or malfunction, it can prevent the proper flow of fluid, causing the engine to struggle at startup.
  

Solution: Inspect the hydraulic lines for any visible signs of leaks and repair them as needed. Check the hydraulic fluid level and refill if necessary. If hydraulic valves are suspected to be the cause, clean or replace the faulty components.
5. Engine Overheating or Seized Components
If the CAT 955K has been running for an extended period, and the engine overheats or components seize up, it may fail to start. This can occur if the cooling system isn’t functioning properly or if components like the water pump, thermostat, or radiator are malfunctioning.
Solution: Check the coolant level and inspect the radiator and water pump for leaks or damage. Replace any worn-out components and ensure the cooling system is working properly.
Real-World Example: A construction company in Arizona found their CAT 955K failing to start after a long day of heavy operation. They traced the issue to an overheated engine caused by a faulty water pump. After replacing the water pump and refilling the coolant, the machine started normally.
Preventive Maintenance Tips
To avoid startup issues in the future, implement a regular maintenance routine for the CAT 955K:

1. Check the battery regularly: Inspect the battery terminals for corrosion and clean them as needed. Test the battery voltage and replace it when it drops below the recommended level.
   
2. Replace fuel filters: Regularly replace the fuel filters to ensure clean fuel flows to the engine.
   
3. Inspect the ignition system: Check the ignition switch, relays, and starter motor periodically to ensure they are working properly.
   
4. Monitor hydraulic fluid levels: Ensure that the hydraulic system is well-maintained and topped off to prevent any starting issues related to hydraulic pressure.
   
5. Maintain the cooling system: Check the coolant levels and inspect the radiator and water pump to avoid overheating problems.
   

Conclusion
If your CAT 955K refuses to start, troubleshooting the issue step by step is the best way to diagnose the problem efficiently. Whether it’s a fuel system issue, battery failure, or ignition switch malfunction, understanding the most common causes will help you get the loader up and running again with minimal downtime.
By following proper maintenance practices and staying vigilant about potential issues, you can ensure that your CAT 955K remains a reliable asset for your business, helping you avoid costly repairs and extend the life of the machine.