850C Series 2 Fuel Control Problems: Diagnosis and Solutions

[MikePhua]

The Case 850C Series 2 is a robust track loader designed for demanding construction and agricultural tasks. With a powerful engine and high hydraulic capacity, it is known for its reliability and versatility. However, as with any piece of heavy machinery, fuel control issues can arise, affecting the loader’s performance. This article will explore common fuel control problems that can occur in the 850C Series 2, potential causes, diagnostic steps, and solutions to help restore the machine’s optimal functionality.
Overview of the Case 850C Series 2
The Case 850C Series 2 is part of the larger Case Construction Equipment lineup, known for manufacturing durable and versatile machines. The 850C was designed for tasks such as material handling, grading, and digging. The machine is powered by a turbocharged diesel engine, offering substantial horsepower and torque to handle demanding jobs. As with many heavy machines, efficient fuel management is critical to maintaining engine performance and preventing costly downtime.
The fuel system in the 850C Series 2 controls how fuel is delivered to the engine, ensuring it runs efficiently and smoothly. Problems in this system, especially with fuel control, can cause significant performance issues, including poor fuel economy, stalling, and even engine failure.
Common Fuel Control Problems in the 850C Series 2

1. Loss of Power and Poor Engine Performance
   One of the most noticeable signs of fuel control issues is a loss of engine power or poor overall performance. If the engine struggles to maintain a steady speed or experiences sudden power drops under load, the issue may lie with the fuel system.
   • Potential Causes:
     • Fuel filter clogging, restricting the flow of fuel to the engine.
       
     • Air in the fuel system due to a loose or damaged fuel line or filter seal.
       
     • Fuel injection system malfunction, leading to incorrect fuel delivery to the engine.
       
     • Dirty or worn fuel injectors, affecting fuel atomization and combustion.
       
   • Solution:
     • Check and replace the fuel filter if clogged.
       
     • Inspect fuel lines and connections for leaks or damage.
       
     • Clean or replace fuel injectors to ensure proper fuel delivery and atomization.
       
     • Bleed the fuel system to remove any trapped air.
       
2. Engine Stalling and Difficulty Restarting
   If the 850C Series 2 experiences stalling during operation or has difficulty restarting after being turned off, fuel flow problems are often to blame. A machine that stalls frequently may exhibit irregular idling or fail to restart after shutting down.
   • Potential Causes:
     • Low fuel levels or air in the fuel system, preventing the engine from receiving adequate fuel.
       
     • Clogged fuel lines or filters restricting the flow.
       
     • Faulty fuel lift pump, which is responsible for drawing fuel from the tank to the injection pump.
       
     • Malfunctioning fuel solenoid that controls the flow of fuel into the engine.
       
   • Solution:
     • Check the fuel level and ensure there is enough fuel in the tank.
       
     • Inspect and replace clogged fuel filters and clean any blocked lines.
       
     • Test the fuel lift pump for proper operation and replace if needed.
       
     • Inspect the fuel solenoid for any electrical issues and replace or repair if necessary.
       
3. Fuel Leaks
   Fuel leaks can occur anywhere in the fuel system, from the tank and lines to the injectors and fuel pump. Even small leaks can lead to fuel loss, reduced engine efficiency, and potential fire hazards.
   • Potential Causes:
     • Cracked or damaged fuel lines and hoses.
       
     • Worn-out fuel pump seals or faulty fuel injectors.
       
     • Loose connections in the fuel system.
       
   • Solution:
     • Inspect fuel lines, hoses, and connectors for signs of wear, cracks, or leaks. Replace any damaged components.
       
     • Check the fuel pump seals for leaks and replace them if necessary.
       
     • Tighten any loose fuel system connections to prevent fuel from escaping.
       
4. Excessive Smoke or Poor Fuel Economy
   Excessive exhaust smoke, particularly black or white smoke, is often an indication of a fuel delivery issue. Black smoke usually signifies that the engine is burning too much fuel, while white smoke could indicate incomplete combustion. Poor fuel economy may also be a side effect of fuel control problems, as the engine struggles to achieve optimal fuel efficiency.
   • Potential Causes:
     • A malfunctioning fuel pump or incorrect fuel delivery pressure.
       
     • A blocked air filter, reducing airflow and causing an imbalance in the air-fuel mixture.
       
     • Faulty fuel injectors that are either leaking or spraying fuel improperly.
       
     • Worn out or miscalibrated fuel control unit.
       
   • Solution:
     • Inspect and replace the fuel filter to ensure proper fuel flow.
       
     • Check and clean the air filter to ensure proper air intake.
       
     • Clean or replace the fuel injectors to ensure they deliver fuel correctly.
       
     • Test and calibrate the fuel control unit to ensure it is providing the correct fuel pressure.
       

Diagnostic Steps for Fuel Control Problems

1. Check Fuel Filters and Lines
   The first step in diagnosing fuel control issues is to check the fuel filter for clogs and inspect the fuel lines for leaks. A clogged filter can restrict fuel flow, while damaged lines may cause air or fuel leaks. Replacing a clogged fuel filter and repairing any leaks can often solve performance issues.
   
2. Inspect Fuel Lift Pump and Fuel Injection System
   The fuel lift pump draws fuel from the tank and pushes it to the injection system. If this pump is not working correctly, the engine may not receive the required fuel pressure. A malfunctioning fuel injection system can lead to improper fuel delivery, affecting engine performance.
   • Test the lift pump for proper fuel pressure.
     
   • Inspect the fuel injectors for wear, clogs, or leaks.
     
3. Bleed the Fuel System
   Air trapped in the fuel system can cause stalling and poor engine performance. Bleeding the fuel system is necessary to remove any air pockets. This process involves opening the bleed valve on the fuel filter or injection pump to release the air.
   
4. Check the Fuel Solenoid and Fuel Control Unit
   The fuel solenoid controls the flow of fuel into the engine, and a malfunction can prevent the engine from starting or cause it to stall. The fuel control unit regulates fuel pressure and delivery, and if it’s miscalibrated, it can lead to improper fuel delivery.
   • Test the solenoid for electrical issues.
     
   • Calibrate or replace the fuel control unit if necessary.
     

Preventive Maintenance Tips

1. Regular Fuel Filter Replacement
   Changing the fuel filter on a regular basis is one of the easiest and most effective ways to prevent fuel control problems. A clogged fuel filter can cause poor engine performance, stalling, and other fuel-related issues.
   
2. Inspect and Clean the Fuel System Regularly
   Clean fuel lines, check for leaks, and ensure that the fuel pump and injectors are functioning correctly. Regular inspections can catch small issues before they lead to more serious problems.
   
3. Use Quality Fuel
   Poor-quality fuel can contribute to clogging and build-up within the fuel system, affecting the performance of the engine. Always use high-quality, clean fuel to keep the system running smoothly.
   
4. Keep the Air Filter Clean
   A clean air filter ensures that the air-fuel mixture is optimal, preventing performance issues related to poor combustion.
   

Conclusion
Fuel control issues in the Case 850C Series 2 can significantly impact the machine’s performance, from poor engine power to stalling and inefficient fuel usage. Diagnosing and fixing problems in the fuel system—whether it’s clogged filters, air in the lines, faulty pumps, or injectors—requires careful inspection and maintenance. By following the diagnostic steps outlined in this article and performing regular preventive maintenance, you can ensure that your 850C loader remains in optimal working condition, minimizing downtime and maximizing productivity on the job site.