Which of the following would be indicative of an ignition system malfunction?

An indicator of an ignition system malfunction is the complete absence of spark during engine cranking. This situation suggests a fundamental issue within the ignition system; it could stem from a failed ignition coil, a malfunctioning crankshaft position sensor, or issues with wiring and connections. Without any spark, the engine will not be able to ignite the air-fuel mixture, leading to an inability to start.

While inconsistent spark strength can suggest problems, it typically indicates a weak or failing ignition system rather than a complete failure. Delayed spark timing might point to timing issues or sensor faults, but it doesn't necessarily mean that the ignition system is entirely non-functional. Additionally, ignition coil overheating can be a sign of failure or load issues, but again, it may not mean there is no spark at all. Therefore, the total lack of spark is the clear and definitive sign of a malfunction that prevents engine operation.