Drivability Practice Exam

Understanding how fuel injectors are timed relative to the engine cycle is what this item tests. In a sequential fuel injection system, each injector fires just before the intake stroke of its own cylinder, in the exact firing order. In non-sequential fuel injection, injectors are not timed to individual cylinders; they fire in groups or all together during the intake event, rather than in cylinder-by-cylinder order. The diagram shows injectors lighting up at the same moment (or in fixed groups) rather than each one firing in strict order, which matches the batch-style firing of non-sequential fuel injection. That pattern best fits this scenario, which is why it’s the correct choice.