Troubleshooting Throttle Control Issues in the New Holland LS170 Skid Steer Loader

[MikePhua]

Introduction
The New Holland LS170 skid steer loader is a versatile and reliable machine commonly used in construction, landscaping, and agriculture. However, like all machinery, it can experience performance issues over time. One such issue is the inability to control the throttle, leading to the engine idling at full throttle upon startup. This problem can be both perplexing and disruptive to operations. Understanding the potential causes and solutions is essential for maintaining the machine's performance and longevity.
Understanding the Throttle Control System
The throttle control system in the LS170 is responsible for regulating the engine's speed by adjusting the fuel supply. This system typically involves a throttle lever or pedal inside the cab, connected via a cable or electronic link to the engine's injection pump. The injection pump modulates the amount of fuel delivered to the engine, thereby controlling its speed.
Common Symptoms of Throttle Control Issues

• Engine Idling at Full Throttle: Upon startup, the engine may idle at maximum speed, regardless of the throttle lever position.
  
• Unresponsive Throttle Lever: Moving the throttle lever may have no effect on engine speed.
  
• Intermittent Throttle Control: Occasionally, the throttle may function correctly after several attempts to restart the engine.
  

Potential Causes and Solutions

1. Sticking Fuel Shutoff Solenoid
   • Cause: The fuel shutoff solenoid controls the flow of fuel to the engine. If it becomes stuck or fails, it can prevent the engine from starting or cause it to idle at full throttle.
     
   • Solution: Inspect the fuel shutoff solenoid for proper operation. If it appears faulty, consider replacing it. Ensure that the solenoid is receiving the correct voltage and is not obstructed.
     
2. Faulty Throttle Cable or Linkage
   • Cause: A broken or disconnected throttle cable can prevent the throttle lever from controlling the engine speed.
     
   • Solution: Inspect the throttle cable and linkage for any signs of wear, damage, or disconnection. Replace any faulty components and ensure proper adjustment.
     
3. Injector Pump Control Rack Issues
   • Cause: The control rack within the injector pump regulates fuel delivery. If it becomes stuck or malfunctions, it can cause the engine to run at full throttle.
     
   • Solution: Inspect the injector pump control rack for freedom of movement. If it is stuck, attempt to free it by gently tapping or applying penetrating oil. In severe cases, the injector pump may need to be removed and overhauled.
     
4. Electrical Issues
   • Cause: Electrical problems, such as blown fuses or poor connections, can disrupt the throttle control system.
     
   • Solution: Check all relevant fuses and electrical connections for continuity and cleanliness. Repair or replace any faulty components as necessary.
     

Preventive Maintenance Tips

• Regular Inspection: Periodically check the throttle control system components for signs of wear or damage.
  
• Clean Fuel: Use clean, high-quality fuel to prevent contamination and ensure proper engine operation.
  
• Proper Storage: Store the machine in a dry, clean environment to protect electrical components and prevent corrosion.
  

Conclusion
Throttle control issues in the New Holland LS170 skid steer loader can stem from various causes, including mechanical failures, electrical problems, or fuel system issues. By systematically diagnosing and addressing these potential causes, operators can restore proper throttle function and maintain the machine's performance. Regular maintenance and prompt attention to symptoms can prevent costly repairs and extend the life of the equipment.