Q: How Does Engine Timing Work?

Engine timing is actually a closely coordinated dance between valve timing, injector timing, and spark timing.

Valve timing is the control of opening and closing the intake and exhaust valves in synchronization with the up / down movement of the pistons. This ensures that air and fuel get into the combustion chambers, the fuel burns at the proper time, the exhaust gases are expelled from the cylinders, and the cycle begins again.

Fuel injection timing is spraying fuel into the intake air stream or combustion chamber while the cylinders are on their intake strokes.

Spark timing is igniting the air/fuel charge at the right time so that the most usable power is created and the least amount of emissions exit the engine.

When you combine all three of these systems together - pistons moving up and down, intake valves opening and closing allowing air and fuel to enter the cylinders, spark plugs igniting the air/fuel mixtures, and exhaust valves opening and closing allowing exhaust gases to exit the cylinders, you have the total effect of engine timing.