Troubleshooting the T-200 Engine Running Wide Open and Not Shutting Down

[MikePhua]

A malfunctioning engine that runs wide open and refuses to shut down is a frustrating issue for operators, especially in equipment like the Bobcat T-200 track loader. This problem can cause significant operational downtime and potentially lead to further damage if not addressed quickly. In this article, we will explore the possible causes of the T-200 engine running wide open, discuss potential troubleshooting methods, and offer insights on how to resolve the issue.
Understanding the T-200 Track Loader and Its Common Components
The Bobcat T-200 is a part of Bobcat's series of compact track loaders designed for a variety of construction, landscaping, and agricultural tasks. The T-200 is powered by a turbocharged diesel engine, known for its power, durability, and versatility. Like other Bobcat machines, it is equipped with a hydraulic system that controls various components, such as the arms, lift mechanisms, and attachments.
When an issue like an engine running wide open occurs, it typically involves the fuel delivery or control system. The T-200's engine is equipped with several critical systems to manage fuel, air, and exhaust, and a failure in any one of these components can cause the engine to malfunction.
Possible Causes of the Engine Running Wide Open

1. Fuel Control Valve Malfunction
   One of the most common causes of an engine running at full speed uncontrollably is a malfunctioning fuel control valve. The fuel control valve regulates the amount of fuel entering the engine, and if it fails to close or is stuck open, the engine will receive too much fuel, causing it to run at full throttle.
   • Symptoms: The engine will suddenly run at high RPMs and cannot be shut off by the operator.
     
   • Solution: Inspect the fuel control valve for blockages or signs of malfunction. If necessary, replace the valve or clean it to restore proper function.
     
2. Sticking or Failed Throttle Linkage
   The throttle linkage connects the accelerator pedal to the engine’s throttle control system. If this linkage becomes worn, bent, or stuck, it can cause the engine to run wide open, even if the operator is not pressing the pedal.
   • Symptoms: The loader will not respond to throttle adjustments, and the engine will continue to run at high RPM.
     
   • Solution: Inspect the throttle linkage for any signs of wear or obstruction. Ensure the linkage is free-moving and adjust it as needed.
     
3. Faulty Engine Control Module (ECM)
   The ECM is responsible for managing various engine functions, including throttle control. A faulty ECM can misinterpret signals from the operator and cause the engine to run at full speed without shutting down.
   • Symptoms: The engine runs erratically or at high RPMs, and the usual shutdown procedure does not work.
     
   • Solution: Perform a diagnostic test to check for any fault codes or error messages related to the ECM. If the ECM is determined to be the problem, it may need to be repaired or replaced.
     
4. Hydraulic System Malfunctions
   The Bobcat T-200 relies on its hydraulic system for controlling not only the loader arms but also throttle control in some models. A malfunction in the hydraulic system could potentially cause erratic engine behavior.
   • Symptoms: The engine may surge or run wide open, particularly when the hydraulic system is under load.
     
   • Solution: Inspect the hydraulic system for leaks, low fluid levels, or malfunctioning valves. Ensure all hydraulic lines and components are functioning properly.
     
5. Fuel Injectors or Governor Issues
   The fuel injectors and governor play an essential role in regulating engine performance. If the fuel injectors become clogged or the governor fails, it can lead to excessive fuel delivery, causing the engine to run too fast.
   • Symptoms: The engine revs uncontrollably, and adjusting the throttle has no effect on speed.
     
   • Solution: Clean or replace the fuel injectors and inspect the governor system for any issues. Regular maintenance of these components can prevent future problems.
     

Troubleshooting and Solutions
To effectively diagnose and fix the issue of the engine running wide open, operators can follow these troubleshooting steps:

1. Step 1: Check the Throttle Control
   • Inspect the throttle pedal and linkage to ensure they are moving freely. If the linkage is stuck, clean or replace the components. Ensure that the throttle cable is not frayed or damaged.
     
2. Step 2: Inspect the Fuel Control Valve
   • Check the fuel control valve to ensure it is functioning correctly. If the valve is stuck open, clean it or replace it. This will help prevent excess fuel from being delivered to the engine.
     
3. Step 3: Test the ECM
   • Perform a diagnostic check using a scan tool to identify any error codes from the ECM. If the ECM is malfunctioning, you may need to reset or replace it.
     
4. Step 4: Examine the Hydraulic System
   • Check the hydraulic fluid levels and inspect for leaks or blockages in the hydraulic lines. If the hydraulic system is malfunctioning, it could affect the throttle response. Ensure that all hydraulic components are operating smoothly.
     
5. Step 5: Clean or Replace Fuel Injectors
   • If the fuel injectors are clogged, clean them thoroughly. If they are damaged, replace them to ensure proper fuel delivery.
     
6. Step 6: Verify the Fuel System
   • Inspect the entire fuel system, including the fuel filter and lines, for any blockages or leaks. Replace any damaged parts and ensure the fuel system is clean and functioning optimally.
     

Preventative Maintenance Tips
To avoid future issues with the T-200 running wide open, here are some preventative maintenance tips:

1. Regular Engine Maintenance
   Regularly change the engine oil and fuel filter to ensure proper engine performance. This will also help prevent dirt and debris from clogging the fuel system or fuel injectors.
   
2. Hydraulic System Inspections
   The hydraulic system is vital to the T-200’s operation. Inspect the hydraulic lines, pumps, and valves regularly for leaks and wear. Clean the system and replace any damaged components to ensure smooth operation.
   
3. Routine Checks of Throttle and Linkage Components
   Make it a habit to check the throttle linkage and pedal assembly during routine maintenance. This can prevent wear and sticking that could cause erratic engine behavior.
   
4. Electrical System Inspections
   Ensure that the electrical wiring is intact and free of corrosion. Poor electrical connections can lead to communication failures between the ECM and other engine components.
   

Conclusion
The Bobcat T-200 track loader is a powerful and versatile machine, but like any piece of heavy equipment, it can experience issues that interfere with its performance. An engine that runs wide open and won’t shut down is a serious issue that needs to be addressed quickly. By following the troubleshooting steps outlined in this article and performing regular maintenance, operators can resolve this issue and ensure the T-200 remains reliable for years to come. Always keep an eye on the fuel control systems, hydraulic components, and electrical systems to avoid future problems and minimize downtime.