The Complete Guide to Air Starters for 5.9 Cummins Engines

Introduction to Air Starters for 5.9 Cummins Engines

Having trouble getting your 5.9 Cummins diesel engine started, especially in cold weather? An air starter may be the solution you need. Air starters provide a powerful burst of air to quickly crank the engine and get it running. In this comprehensive guide, we'll cover everything you need to know about selecting, installing, and using an air starter for your Cummins 5.9L diesel engine.

How Air Starters Work

Air starters work by storing compressed air in an onboard tank. When you engage the starter, the stored air is released, causing a turbine wheel to quickly spin. This turbine wheel is connected to a gearbox that engages the flywheel, turning the engine over. The rushing air creates tremendous torque, allowing an air starter to crank an engine over much faster than standard electric starters.

This faster cranking speed is key for starting diesel engines, especially in cold weather. Diesels need to reach a minimum RPM quickly to start the combustion process. Slow cranking from weak batteries or cold oil often leads to extended cranking times, putting excessive strain on the starter motor.

Air starters eliminate this problem by providing instant high-speed cranking to get the engine spinning. The air stored in the tank propels the flywheel without relying on battery power or engine oil viscosity.

Benefits of Air Starters

There are several key benefits that make air starters a valuable addition for Cummins 5.9L engines:

• Reliable starting in cold weather - Air starters provide reliable starts down to -40°F.
• Faster cranking speed - Air starters crank up to 3x faster than electric starters.
• Reduced starter wear - The high torque prevents excessive starter grinding and wear.
• Lightweight - Air starters weigh less than electric units.
• Compact size - Air starter units are relatively small and mount easily.
• Maintenance-free operation - Air starters require no regular maintenance.
• Emergency starting ability - Air starters can start a dead battery.
• Long lifespan - Air starters generally last 1 million cycles before rebuild.

Choosing an Air Starter for 5.9 Cummins

If you've decided an air starter is right for your Cummins engine, choosing the correct model is important. Here are the key factors to consider:

Starter Power

Air starter power is measured in foot-pounds of torque. A starter must be matched to the size of your engine to provide enough cranking RPM. Most 5.9L Cummins engines require 600-1000 ft-lb starters. Oversizing the starter adds unnecessary weight and cost.

Drive Size

Air starters connect to the engine flywheel via a drive pinion gear. Make sure the starter drive gear correctly engages the ring gear on your engine's flywheel. Common 5.9L Cummins flywheels have ring gears measuring 11.5" or 14".

Electrical System

While air starters don't rely on battery power for cranking, a 12V or 24V electric solenoid is required to engage the starter. Make sure your starter matches your truck's electrical system to ensure proper operation.

Mounting

Consider how and where the air starter will mount on your Cummins engine. Starters come in different mounting configurations to properly orient the drive gear. Common mounting options are flange, pedestal, and transmission mount.

Air System

Your air starter will require a compressed air source, such as the truck's air brake system. Make sure the starter's air inlet fitting properly connects to your air system. The air tank on the starter unit will also need to be periodically recharged with a compressor.

Price

Air starters for the 5.9L Cummins range from about $700 up to $1500 depending on the power and features. While not inexpensive, they can provide years of reliable service.

Installing an Air Starter on a 5.9 Cummins

When installing your new air starter, be sure to follow all instructions from the manufacturer. We recommend having a diesel mechanic perform the installation if you are not familiar with working on diesel engines.

Some key installation steps include:

• Disconnecting the battery before starting work.
• Removing the existing electric starter.
• Mounting the new air starter properly aligned to the flywheel.
• Connecting all required air lines and wiring.
• Testing for leaks in the air system.
• Verifying proper engagement of the drive gear.
• Reconnecting battery power and recharging air tank.
• Testing starter operation before starting engine.

Proper alignment of the drive gear is critical so take your time with this step. Also ensure all mounting fasteners are tight and proper thread locker is used.

Using Your Air Starter

Once your air starter is mounted and connected, using it to start your Cummins engine takes just a few simple steps:

1. Build up air pressure - The starter's tank must be charged to the correct PSI for operation. This requires running the air compressor to fill the tank.
2. Disable electric starter - Shut off the truck's key switch or pull the starter relay to avoid gear clash.
3. Engage air starter - Turn on the starter switch or push button to release stored air and crank the engine.
4. Let engine idle - After startup, allow a brief idle period before driving to circulate oil.

Your specific air starter may have additional features like thermostatically controlled heating to further aid cold weather starts. Refer to the manufacturer instructions for operational details.

With an air starter properly installed, starting your Cummins engine becomes quick and hassle-free, even on the coldest winter days. Just recharge the starter tank periodically and enjoy reliable operation for years to come.

Maintenance Tips for Air Starters

While air starters are generally maintenance-free, some periodic care will keep your starter in peak condition. Here are a few maintenance best practices:

Drain Moisture from Air Tank

Over time, moisture can condense inside the starter's air tank. Draining the tank periodically helps prevent corrosion issues. Most tanks have a ball or petcock drain valve. Open this valve briefly to vent out moisture after use.

Check Drive Gear

Examine the drive gear teeth that engage the flywheel. Look for any cracked, chipped, or badly worn teeth that could slip under load. Replace damaged drive gears to prevent flywheel damage.

Test Starter Operation

Periodically test the starter by engaging it without cranking the engine. Listen for abnormal sounds that could indicate worn bearings, scraping, or grinding issues inside the unit. The starter should spin smoothly and quietly.

Inspect Mounting

Check that all mounting bolts remain properly tightened over time. Loose bolts can cause misalignment and premature gear wear. Add thread locker compound to ensure bolts stay tight.

Keep Air System Charged

Maintain adequate pressure in the air brake system. Starters require high flow at 90-120 PSI to operate properly. Inspect all air lines and fittings for leaks.

Check Electrical Wiring

Inspect the solenoid wiring harness and connections. Repair any frayed or corroded wires that could cause intermittent electrical issues.

Troubleshooting Common Air Starter Problems

While air starters are generally quite durable, issues can arise over time. Here are some common problems and troubleshooting tips:

Starter Engages But Doesn't Crank

If the starter engages but doesn't turn over the engine, the air tank may have insufficient pressure. Below 60 PSI may not generate enough torque. Charge the air system to 100 PSI and test again. Insufficient air flow can also cause this issue.

Starter Spins Too Slowly

Slow cranking speed is another sign of low air tank pressure. Check for air leaks in the lines feeding the starter. Damaged or worn drive gears can also prevent the starter achieving full RPM.

Loud Knocking or Grinding

Gear clashing noises point to drive gear damage or misalignment issues. Ensure the starter is properly mounted. Inspect the flywheel ring gear and starter drive gear for excessive wear or broken teeth.

Starter Engages Continuously

If the starter spins constantly and won't shut off, there is likely an electrical short in the solenoid or starter relay. Immediately disable the starter to prevent gear damage. Check all wiring for loose connections or bare spots.

Starter Won't Engage

When the starter won't engage at all, start by testing the battery and cables to ensure ample voltage is present. Clean any corroded battery terminals or ground points. If voltage is good, the solenoid or relay contacts may need cleaning or replacement.

Conclusion

Installing an air starter provides a great way to get your Cummins 5.9L engine cranking quickly and reliably, even in extremely cold weather. Take the time to properly select a starter with adequate power and correct mounting for your application. With periodic maintenance and proper care, your air starter should deliver years of trouble-free performance.

FAQs

How do air starters work?

Air starters work by storing compressed air in an onboard tank. When engaged, this air spins a turbine connected to the starter drive gear, turning the engine over. The stored air can turn the starter much faster than battery-powered electric starters.

What PSI do air starters require?

Most air starters require a minimum air pressure of 90-120 PSI to generate sufficient cranking torque. Always maintain adequate air pressure to the starter.

How long do air starters last?

With proper maintenance, air starters can last for over 1 million start cycles. Rebuilding the starter can extend the lifespan further. The drive gears will wear over time and require periodic replacement.

How do I mount an air starter?

Proper mounting alignment is critical. The starter must be positioned so the drive gear correctly engages with the flywheel ring gear. Improper alignment can lead to gear damage. Follow all manufacturer instructions.

Why won't my air starter engage?

If the starter won't engage, first check for sufficient air pressure. Also verify battery voltage is reaching the starter solenoid or relay. The electrical connections should be clean and tight. The solenoid may need to be replaced if faulty.