Drivability Practice Exam

Ignition timing determines when the spark plug fires in relation to the piston's position, and getting it out of sync changes how the air–fuel mix burns. If the timing is too advanced, the mixture can ignite too early, producing a high-pressure pulse while the piston is still moving upward, which causes engine knock and places extra stress on components. If the timing is too retarded, combustion happens later, peak pressure occurs after the piston has passed top dead center, reducing the effective cylinder pressure and leading to a noticeable loss of power and efficiency. In both cases, the engine’s performance suffers and noise or heat may increase, rather than improving fuel economy or staying cooler. The option that describes knocking and reduced power matches the typical consequences of incorrect ignition timing. Immediate starter motor failure isn’t a direct result of timing settings, since the starter relates to electrical engagement and engine cranking, not the combustion timing once the engine is running.