Engines 101

Engines look complicated until you simplify them. Here’s the core: an engine is an air pump. Power is how effectively it moves air and turns that into pressure on the piston.

The 4 strokes (quick)

• Intake: air enters
• Compression: air/fuel is squeezed
• Power: combustion pushes piston
• Exhaust: spent gases leave

Air (load) is everything

The ECU needs to know how much air the engine is taking in. That “engine load” can be measured by: MAF (direct airflow) or estimated with MAP (manifold pressure) + RPM + temp.

Fuel: more isn’t safer forever

Fuel cools combustion, but too rich can wash cylinders, foul plugs, and reduce power. Too lean can raise temps and increase knock risk. The goal is “right fuel for the situation.”

Spark timing: the silent power maker

Timing is when the spark occurs relative to piston position. Too advanced can cause knock. Too retarded makes it feel lazy and hot. The goal is peak cylinder pressure at the right moment.

Compression + mechanical health

Before tuning, make sure the engine is healthy. Tuning can’t fix bad compression, weak fuel pressure, vacuum leaks, or failing ignition parts.

Basic troubleshooting mindset