Firing Order
The order in which each of the cylinders in a multi-cylinder engine fires (power stroke). (Example: A four-cylinder engine’s firing order could be 1-4-3-2. This means that the number 1 cylinder fires, then the number 4 cylinder fires, then the number 3 cylinder fires, and so on.) Engines are designed so that power strokes are as uniform as possible; as the crankshaft rotates a certain number of degrees, one of the cylinders will go through a power stroke. This reduces vibration and allows the power generated by the engine to be applied to the load in a smoother fashion than if they were all to fire at once or in odd intervals.