An engine's firing order is the sequence that each cylinder is used in power delivery. The firing order for the 6.6L turbo diesel V8 in the 2004 Chevrolet Silverado 2500 2WD is 1-2-7-8-4-5-6-3.
In a gasoline engine, the distributor or Engine Control Unit sends electricity to individual spark plugs to ignite fuel in each cylinder in a specific order. In a diesel engine it is determined by the order in which fuel is injected into each cylinder.
Engine firing orders always start with cylinder number one, which on this engine is located at the front left of the engine from the driver's point of view.
GM V8 cylinders are numbered 1-3-5-7 on the left (driver's) side of the engine, and 2-4-6-8 on the right (passenger) side.
