What Happens If the Ignition Timing Is Not Set Properly?

Vehicle operators set ignition timing via the specified timing advance. Timing advance, meaning the number of degrees set on the timer before top dead center, will determine the exact point at which a spark ignites the air and fuel mixture. If an owner or mechanic sets the ignition time properly, maximum pressure occurs in the cylinder, enabling optimum air and fuel mixing and combustion, and efficient engine performance.

Setting the timing at a high position, or at a degree too advanced relative to the position of the piston during the compression stroke, causes the combustion mixture to exert force against the piston. This force may result in engine damage, engine failure, or pre-ignition system damage.

If the ignition timing is set too far back, making it too retarded relative to the position of the piston, pressure in the cylinder maximizes after the piston has descended too far in the cylinder. The retarded spark results in higher emissions, less fuel efficiency due to a higher level of burned fuel and reduced engine power.