Why a John Deere 444C Loader May Show No Fuel at Injectors After Long-Term Storage

[MikePhua]

John Deere 444C Loader Overview
The John Deere 444C is a mid-size wheel loader introduced in the mid-1980s, designed for construction, municipal, and agricultural use. Powered by a naturally aspirated or turbocharged diesel engine, typically the JD 6.6L inline-six, the 444C features a powershift transmission, hydraulic loader arms, and a rugged frame suited for material handling and light excavation. With an operating weight of around 22,000 pounds and a bucket capacity of 2.5 cubic yards, it became a popular choice for small contractors and public works departments.
John Deere, founded in 1837, has long been a leader in agricultural and construction equipment. The 444C was part of its evolution toward more operator-friendly loaders, incorporating improved cab ergonomics and simplified service access. Many units remain in service today, though some have sat idle for years, leading to fuel system issues.
Symptoms of Fuel Delivery Failure
When attempting to restart a 444C after a decade of inactivity, one may encounter a complete lack of fuel at the injector lines despite fuel reaching the injection pump inlet. Common symptoms include:

• No fuel dribble from cracked injector lines during cranking
  
• No return flow from the injection pump to the tank
  
• Pressure buildup behind the pump’s bleed screw, but no delivery to injectors
  

These symptoms suggest internal blockage or mechanical failure within the injection pump, particularly in the metering valve or pumping plungers.
Terminology Notes

• Injection Pump: A mechanical device that meters and pressurizes fuel for delivery to the injectors.
  
• Metering Valve (MV): A component inside the pump that regulates fuel flow into the hydraulic head.
  
• Solenoid: An electrically actuated valve that enables or disables fuel flow based on ignition signal.
  
• Transfer Pump: A low-pressure pump that feeds fuel into the injection pump housing.
  

Root Causes and Diagnostic Path
Several issues can prevent fuel from reaching the injectors:

• Stuck Metering Valve: After years of sitting, varnish and sediment can seize the MV. Removing the top cover and manually checking its movement is essential.
  
• Stuck Pumping Plungers: Internal plungers may be seized due to corrosion. These require full pump disassembly or replacement.
  
• Weak Solenoid Voltage: If voltage drops below 9.5V during cranking, the solenoid may close prematurely, cutting off fuel.
  
• Broken Drive Shaft: A rare but serious failure where the pump shaft shears, preventing internal rotation. However, pressure behind the bleed screw often rules this out.
  

Field Anecdote and Repair Strategy
In Massachusetts, a technician attempted to revive a 1986 444C that had been parked for ten years. After replacing the starter and filters, he found no fuel at the injectors. The solenoid clicked audibly, but voltage dropped to 9.2V during cranking. He removed the pump’s top cover and confirmed the metering valve moved freely. Despite this, fuel still didn’t reach the injectors.
Eventually, he replaced the injection pump with a used unit from a tractor supply store. After 20 cranking cycles, fuel began returning to the tank and the injector lines showed signs of pressure. The starter began to overheat, so he paused to avoid damage. The new pump resolved the delivery issue, but concerns remained about cylinder compression due to water ingress during storage.
Recommendations for Technicians

• Check Solenoid Voltage Under Load: Ensure stable voltage above 10V during cranking.
  
• Manually Inspect Metering Valve: Remove the top cover and verify free movement.
  
• Prime the Pump Using Transfer Lever: Fill the pump housing before cranking to reduce starter strain.
  
• Replace Pump if Plungers Are Stuck: Internal seizure often requires professional rebuild or replacement.
  
• Test Cylinder Compression: Water in cylinders may have caused ring or valve damage.
  

Final Thoughts
A John Deere 444C showing no fuel at injectors after long-term storage likely suffers from internal injection pump issues, especially a stuck metering valve or plungers. With careful voltage testing, manual inspection, and pump replacement if needed, fuel delivery can be restored. However, engine health must also be verified before investing further in revival. Machines left idle for years often require a full systems check to ensure safe and reliable operation.