Case 580C Diesel Engine: Troubleshooting No Start Despite Fuel at Injectors

[MikePhua]

Introduction
The Case 580C backhoe loader, equipped with the Case D207 engine, is renowned for its reliability and versatility in construction and agricultural applications. However, owners occasionally encounter a perplexing issue: the engine cranks but fails to start, even when fuel is present at the injectors. This scenario suggests that while fuel reaches the injectors, it may not be delivered in the correct quantity or timing to achieve combustion.
Understanding the Fuel System
At the heart of the fuel delivery system is the Stanadyne Roosa-Master rotary injection pump. This pump is responsible for metering and pressurizing fuel before it's delivered to the injectors. The system operates under high pressure, typically around 2800 psi, to ensure efficient atomization of fuel for optimal combustion.
Common Causes of No Start Despite Fuel at Injectors

1. Injector Pump Malfunction
   Even with fuel present at the injectors, the engine may not start if the injector pump isn't delivering fuel at the correct pressure or timing. Common issues include:
   • Sticking Governor Linkage: The governor mechanism regulates fuel delivery. If the linkage becomes stuck, it can prevent proper fuel metering. This is often due to internal wear or contamination.
     
   • Damaged Components: Parts like the governor weight retainer ring, often made of plastic, can deteriorate over time, leading to debris that clogs fuel passages. This can disrupt fuel flow and cause starting issues .
     
2. Air in the Fuel System
   Air pockets in the fuel lines can impede fuel flow, leading to insufficient fuel reaching the injectors. Even if fuel is present at the injectors, air can prevent the injectors from delivering fuel effectively. Thorough bleeding of the fuel system is essential to remove any trapped air .
   
3. Clogged or Faulty Injectors
   Injectors can become clogged due to contaminants in the fuel, such as rust or debris. This can prevent them from atomizing the fuel properly, leading to poor combustion and starting difficulties. Testing and cleaning the injectors can help determine if they are functioning correctly.
   
4. Compression Issues
   Diesel engines require high compression to ignite the fuel-air mixture. Low compression, due to worn piston rings or valves, can result in inadequate combustion, preventing the engine from starting. Performing a compression test can help diagnose this issue .
   

Diagnostic Steps

1. Check Fuel Delivery
   • Ensure fuel is reaching the injector pump.
     
   • Crack open the injector lines and observe if fuel is being delivered when the engine is cranked.
     
2. Bleed the Fuel System
   • Loosen the bleed screws on the fuel filter housing and injector pump.
     
   • Crank the engine to expel air until a steady stream of fuel flows without bubbles.
     
3. Inspect the Injector Pump
   • Remove the top cover of the injector pump to check for stuck governor linkage or damaged components.
     
   • Clean any debris and ensure all parts move freely.
     
4. Test the Injectors
   • Remove one injector and connect it to the fuel line.
     
   • Crank the engine and observe if fuel is being injected.
     
   • If no fuel is injected, the issue may lie with the injector or the injector pump.
     
5. Perform a Compression Test
   • Remove an injector and install a compression tester.
     
   • Crank the engine and record the compression readings.
     
   • Compare the readings to the manufacturer's specifications to determine if compression is adequate.
     

Conclusion
Diagnosing and resolving starting issues in the Case 580C, despite fuel presence at the injectors, requires a systematic approach. By thoroughly checking the fuel delivery system, injector pump, injectors, and engine compression, most issues can be identified and addressed. Regular maintenance and prompt attention to potential problems can ensure the longevity and reliability of the machine.