5411556 | Genuine Cummins® Ignition Coil for Cummins ISX

1. Battery Supplies Low Voltage

The vehicle battery provides about 12 volts to the ignition system.

2. Ignition Coil Receives the Power

The ignition coil takes that low voltage and stores energy in its internal windings (like a small transformer).

3. Magnetic Field Builds and Collapses

When the engine control module (or older ignition module) switches the current off:

• The magnetic field inside the coil collapses

• This creates a high-voltage surge

4. High Voltage Is Created

The ignition coil boosts 12 volts into 20,000–40,000+ volts.

5. Voltage Travels to the Spark Plug

The high voltage moves:

• Through a distributor (older systems), or

• Directly to the spark plug (coil-on-plug systems)

6. Spark Plug Fires

The spark jumps across the spark plug gap.

7. Air-Fuel Mixture Ignites

The spark ignites the compressed air-fuel mixture in the cylinder.

8. Combustion Produces Power

The explosion pushes the piston down, creating engine power.

1. Slight Engine Hesitation

• Small stumble during acceleration

• Feels like brief power loss

• Happens occasionally

This is usually the earliest warning sign.

2. Rough Idle

• Engine shakes while stopped

• RPM fluctuates

• Feels uneven or vibrating

A weak coil may not fire consistently at low speed.

3. Engine Misfire

• Noticeable jerking while driving

• Check Engine Light may turn on

• Misfire codes (like P0301, P0302, etc.)

One cylinder may not be firing properly.

4. Loss of Power

• Poor acceleration

• Sluggish performance

• Difficulty climbing hills

The engine is running on fewer working cylinders.

5. Poor Fuel Economy

• Using more fuel than normal

• Unburned fuel due to weak spark

6. Hard Starting

• Engine cranks longer before starting

• Sometimes starts then stalls

Spark may be too weak to ignite fuel properly.

7. Backfiring or Strong Fuel Smell

• Popping from exhaust

• Smell of raw gasoline

Fuel is entering the exhaust system without burning.

8. Engine Stalling

• Engine suddenly shuts off

• May restart after cooling down

Heat can cause internal coil failure.

9. No Start Condition (Severe Failure)

• Engine cranks but won’t start

• Complete loss of spark

This happens if the coil fully fails.