John Deere 328 Skid Steer Engine Surging and Fuel System Remedies

[MikePhua]

The 328 and John Deere’s Mid-Frame Loader Lineage
The John Deere 328 skid steer loader was introduced in the mid-2000s as part of the company’s 300-series lineup, designed to deliver high breakout force, hydraulic versatility, and operator comfort in a compact footprint. With an operating weight around 8,000 lbs and a rated operating capacity of 2,800 lbs, the 328 was widely adopted by contractors, municipalities, and agricultural operators.
Powered by a 5-cylinder turbocharged diesel engine—often the John Deere PowerTech 4024 or a variant—the 328 offered smooth torque delivery and fuel efficiency. However, as these machines age, some units exhibit engine surging under load, a symptom that points to deeper issues in the fuel delivery and control systems.
Understanding Engine Surging in Diesel Systems
Engine surging refers to rhythmic fluctuations in RPM, typically occurring under partial or full load. In diesel engines, this behavior is often caused by inconsistent fuel delivery, timing irregularities, or feedback loop instability in the governor system.
Common symptoms include:

• RPM oscillation of 100–300 revolutions during operation
  
• Smooth idle but erratic behavior under hydraulic load
  
• Audible pitch changes in engine tone
  
• Temporary power loss followed by recovery
  
• Increased fuel consumption or exhaust smoke
  

In one documented case, a 328 with over 9,000 hours began surging during bucket lifts. The operator replaced the fuel filter and added diesel conditioner, which improved performance temporarily but did not eliminate the issue.
Root Causes and Diagnostic Pathways
Surging in the 5-cylinder engine powering the 328 can stem from several sources:

• Fuel rack binding due to varnish or wear
  
• Governor capsule misadjustment or spring fatigue
  
• Air intrusion in fuel lines or filter housing
  
• Dirty or worn injection nozzles
  
• Weak lift pump unable to maintain consistent pressure
  
• Electronic control module misinterpreting sensor feedback
  

Diagnostic steps include:

• Inspecting fuel lines for bubbles or leaks
  
• Replacing primary and secondary fuel filters
  
• Testing injection pump pressure and timing
  
• Cleaning or replacing injectors
  
• Checking governor capsule preload and linkage
  
• Scanning for fault codes via service port
  

A technician in Alberta resolved surging by adjusting the torque capsule inside the injection pump, a delicate procedure requiring special tools and a service manual. The adjustment stabilized RPM and restored full hydraulic responsiveness.
Fuel Rack and Governor Capsule Behavior
The fuel rack is a mechanical linkage inside the injection pump that regulates fuel quantity based on throttle input and load. Over time, it can stick due to varnish buildup or wear, causing erratic fuel delivery.
The governor capsule, often spring-loaded, modulates rack movement to maintain steady RPM. If the spring weakens or the preload is incorrect, the system can oscillate, leading to surging.
Solutions include:

• Cleaning the fuel rack with diesel-compatible solvent
  
• Replacing worn springs and seals in the governor capsule
  
• Adjusting preload using manufacturer specifications
  
• Lubricating linkage points with anti-seize compound
  
• Verifying rack travel range and return behavior
  

In one rebuild, a restorer in Oregon disassembled the injection pump and found the rack scored and partially seized. After polishing and reassembly, the engine ran smoothly under all conditions.
Preventive Maintenance and Fuel System Health
To prevent surging and extend engine life:

• Use high-quality diesel with low sulfur content
  
• Add fuel conditioner monthly to reduce varnish and moisture
  
• Replace fuel filters every 250 hours
  
• Bleed air from the system after filter changes
  
• Inspect lift pump diaphragm and replace if weak
  
• Monitor injector spray pattern and replace nozzles as needed
  

A fleet manager in Texas implemented a fuel system inspection protocol and reduced surging incidents by 70% across his skid steer fleet.
Field Stories and Practical Fixes
In 2022, a landscaping crew in Ontario experienced surging on a 328 during grading work. After replacing filters and checking injectors, the issue persisted. A diesel specialist traced the problem to a misadjusted governor capsule. After recalibration, the loader returned to full performance.
Another example comes from a demolition team in Florida, where surging occurred during hydraulic hammer use. The technician found air leaks at the filter housing and replaced the seals. The engine stabilized immediately.
Conclusion and Recommendations
Engine surging in the John Deere 328 is often a symptom of fuel system imbalance, mechanical wear, or governor miscalibration. With targeted diagnostics and careful adjustment, the issue can be resolved without major overhaul.
Recommendations include:

• Inspect and clean the fuel rack and governor capsule
  
• Replace filters and bleed air regularly
  
• Use diesel conditioner to prevent varnish buildup
  
• Monitor injector performance and replace as needed
  
• Document adjustments and service intervals for future reference
  

With proper care, the 328 remains a powerful and responsive skid steer—ready to lift, grade, and haul with precision across demanding job sites.