As a mechanical engineering expert with a focus on automotive technology, I can provide a comprehensive explanation of what causes an engine to run on. An engine, specifically an internal combustion engine, operates by converting the chemical energy from fuel into mechanical energy through a series of controlled explosions within its cylinders. The process is intricate and involves several components and steps, which I will detail below.

The Four Stroke Cycle
The operation of an engine is typically divided into four distinct strokes: the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. These strokes are part of a continuous cycle that repeats with each rotation of the crankshaft.


1. Intake Stroke: The engine draws in a mixture of air and fuel through the intake valve as the piston moves downward.

2. Compression Stroke: The air-fuel mixture is compressed by the upward movement of the piston, which also increases its temperature and pressure.

3. Power Stroke: In a gasoline engine, the spark plug ignites the compressed mixture, causing a mini explosion that pushes the piston downward, creating power.

4. Exhaust Stroke: The piston moves back up, expelling the exhaust gases through the exhaust valve.

Ignition System
The ignition system plays a crucial role in the operation of a gasoline engine. It consists of components such as the spark plugs, ignition coil, distributor, and ignition switch. The spark plugs are responsible for creating a spark at the right moment to ignite the compressed air-fuel mixture.

Fuel System
The fuel system delivers fuel to the engine. It includes the fuel tank, fuel pump, fuel filter, fuel lines, and fuel injectors. Modern engines use fuel injectors to precisely control the amount of fuel that is mixed with air and delivered to the combustion chamber.

Lubrication System
The engine's moving parts need to be lubricated to reduce friction and prevent wear. The lubrication system circulates oil throughout the engine, ensuring that all parts are adequately protected.

Cooling System
Excessive heat can damage an engine, so the cooling system is essential. It removes heat from the engine by circulating coolant through the engine block and head, and then dissipating it into the air or to the radiator for cooling.

The Diesel Effect
In the context of your question, the term "diesel" refers to the diesel engine's principle of operation, which is different from a gasoline engine. A diesel engine does not use spark plugs to ignite the fuel. Instead, it relies on the high compression of air to heat it to the point where the fuel ignites spontaneously when injected into the combustion chamber. This is known as "compression ignition" and is the defining characteristic of diesel engines.

Causes of Engine Misfires
While the term "running-on" is not a standard term in engine operation, it seems to refer to an engine misfiring or not igniting the air-fuel mixture properly. Several factors can cause an engine to misfire:


1. Faulty Ignition System: Worn spark plugs or a malfunctioning ignition coil can prevent the spark from occurring.

2. Fuel Delivery Issues: Problems with the fuel pump, fuel injectors, or fuel pressure can lead to insufficient fuel reaching the combustion chamber.

3. Air Intake Problems: A clogged air filter or issues with the intake manifold can restrict the flow of air.

4. Mechanical Failures: Worn or damaged piston rings, valves, or cylinder walls can affect compression and lead to misfires.

5. Sensor Failures: Sensors that monitor engine conditions and adjust the air-fuel mixture can fail, leading to an improper mixture ratio.

Prevention and Maintenance
To prevent engine misfires and ensure smooth operation, regular maintenance is essential. This includes:

- Regular oil changes to maintain lubrication.
- Replacing air filters and cleaning or replacing the fuel filter periodically.
- Checking and replacing spark plugs and ignition components as needed.
- Ensuring the fuel system is functioning correctly with no leaks or blockages.
- Keeping the cooling system in good condition to prevent overheating.

In conclusion, an engine runs on through a series of well-coordinated processes that involve the intake, compression, power, and exhaust strokes. The ignition and fuel systems are critical for igniting the fuel and delivering it to the engine, while the lubrication and cooling systems ensure the longevity and efficiency of the engine's operation. Understanding these components and maintaining them properly is key to preventing misfires and ensuring the engine runs smoothly.

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Running-on occurs when the fuel/air mixture in the cylinders ignites without a spark. This is known as the dieselling effect because it is caused by the fuel igniting spontaneously in the combustion chambers, which is what occurs (deliberately) in a diesel engine. There are several causes.read more >>