Cold Start Injection Systems in Diesel Equipment

[MikePhua]

Why Cold Start Injection Matters
Cold weather poses a serious challenge for diesel engines, especially in older or mechanically governed machines. Unlike gasoline engines, diesel relies on compression ignition, which demands high cylinder temperatures to vaporize and ignite fuel. When ambient temperatures drop below 10°C (50°F), starting becomes difficult due to thickened oil, reduced battery output, and poor fuel atomization. Cold start injection systems were developed to address this issue by introducing auxiliary heat or fuel to aid combustion during startup.
Terminology Notes

• Cold Start Injection: A system that delivers a small amount of fuel or heating agent into the intake or combustion chamber to assist ignition in cold conditions.
  
• Ether Injection: A method using ether-based fluid sprayed into the intake to ignite easily and raise cylinder temperature.
  
• Glow Plug: An electrically heated element inside the combustion chamber that preheats air for better fuel ignition.
  
• Block Heater: An external electric heater installed in the engine block to maintain coolant and oil temperature overnight.
  
• Fluid Film: A lanolin-based lubricant sometimes used as a cold start aid due to its flammability and lubricating properties.
  

Types of Cold Start Aids and Their Mechanisms
Cold start systems vary by engine type and region. Common solutions include:

• Ether injection systems, often factory-installed on older John Deere and Case machines, deliver a metered shot of ether into the intake manifold. While effective, misuse can damage pistons or wash away cylinder lubrication.
  
• Glow plug systems, standard on many Perkins and Cummins engines, heat the combustion chamber directly. These are reliable but draw significant current and require a few seconds of preheating.
  
• Diesel-fired intake heaters, such as CAV cold start aids, burn a small amount of diesel in the intake manifold to warm incoming air. These systems are efficient and use less electrical power than glow plugs.
  
• Propane injection systems, though less common, have been explored as alternatives to ether. They offer cleaner combustion but require careful metering and safety precautions.
  

In one Canadian mining operation, operators retrofitted their fleet with diesel-fired intake heaters after repeated ether-related engine failures. The change reduced cold start complaints by 80% and extended engine life.
Installation and Integration Tips
Installing a cold start system requires attention to engine layout and electrical capacity. Key steps include:

• Identify a suitable location on the intake manifold for heater or injector installation. If no flat surface exists, weld a mounting pad and tap threads.
  
• Ensure fuel supply is gravity-fed or routed from injector return lines to maintain consistent flow.
  
• Wire the system through a relay and switch, ideally with a timer or temperature sensor to prevent overuse.
  
• Test the system in moderate temperatures before relying on it in extreme cold.
  

A technician in Montana once installed a CAV-style heater on a Cummins VT-555 by drilling into the intake and plumbing a small diesel tank. The system worked flawlessly and eliminated the need for ether.
Operational Best Practices
To maximize cold start reliability:

• Plug in block heaters overnight, not just for a few hours. Most need 6–8 hours to warm the coolant and oil sufficiently.
  
• Cycle glow plugs or intake heaters fully before cranking.
  
• Avoid excessive cranking; if the engine doesn’t start within 10 seconds, pause and reheat.
  
• Turn the steering wheel during cranking on machines with front-mounted hydraulic pumps. This can destroke the pump and reduce starter load.
  
• Check battery voltage and connections regularly. Cold weather reduces battery capacity by up to 50%.
  

In a Wisconsin farm, operators discovered that turning the wheel during cranking on a Deere backhoe reduced hydraulic resistance and improved starter speed—a trick now taught to new hires.
Risks and Misconceptions
While ether is widely used, it carries risks:

• Overuse can cause pre-ignition, damaging pistons and rings.
  
• It strips oil from cylinder walls, increasing wear.
  
• If injected while glow plugs are active, it can ignite prematurely.
  

Propane systems, though cleaner, can be dangerous if not properly regulated. One operator in Alaska attempted a DIY propane start system and caused a manifold explosion due to over-injection.
Fluid Film, a lanolin-based spray, has been used experimentally as a cold start aid. Some users report improved startup, but its performance varies with temperature and delivery method. In extreme cold, even the spray cans may fail to function.
Maintenance and Troubleshooting
If cold start issues persist:

• Verify block heater function by feeling warmth near the plug-in point.
  
• Inspect fuel lines for air leaks that may cause loss of prime.
  
• Check glow plug resistance and replace any that test open.
  
• Clean intake heaters and ensure fuel delivery is unobstructed.
  
• Upgrade starter wiring if voltage drop is excessive—some older machines suffer from undersized cables.
  

A Case 1845 skid steer in Pennsylvania showed hard starts below 50°F despite a working block heater. After upgrading the starter wiring and installing a booster solenoid, the machine started reliably even in sub-freezing conditions.
Final Thoughts
Cold start injection systems are essential for diesel equipment operating in harsh climates. Whether using ether, glow plugs, diesel-fired heaters, or alternative fuels, the key is proper installation, cautious operation, and regular maintenance. With the right setup, even the most stubborn diesel can roar to life on a frosty morning. In the world of heavy equipment, a reliable cold start isn’t just convenience—it’s survival.