A piggyback ignition module would most likely modify the signal from the PCM to control __________.

A piggyback ignition module would most likely modify the signal from the PCM to control __________.

• A. Injector Duty Cycle
• B. Spark Timing
• C. Valve Timing
• D. Timing of exhaust gas recirculation

Answer: (B)

This question tests understanding that a piggyback ignition module changes when the spark fires by altering the ignition timing signal coming from the PCM. It sits in the wiring path to the ignition system and tweaks the timing so the coil fires earlier or later than the PCM’s original plan, aiming to improve power, throttle response, or efficiency. The injector duty cycle controls how long fuel injectors stay open. That signal comes from the PCM’s fuel control, not the ignition module, so it isn’t the target of a piggyback ignition device. Valve timing refers to when the valves open and close, governed by the camshaft and valve timing systems, not the ignition spark. Timing of exhaust gas recirculation is managed by the EGR system and related controls, not the ignition signal. Therefore, the spark timing is the aspect the piggyback module is designed to modify.

This question tests understanding that a piggyback ignition module changes when the spark fires by altering the ignition timing signal coming from the PCM. It sits in the wiring path to the ignition system and tweaks the timing so the coil fires earlier or later than the PCM’s original plan, aiming to improve power, throttle response, or efficiency.

The injector duty cycle controls how long fuel injectors stay open. That signal comes from the PCM’s fuel control, not the ignition module, so it isn’t the target of a piggyback ignition device. Valve timing refers to when the valves open and close, governed by the camshaft and valve timing systems, not the ignition spark. Timing of exhaust gas recirculation is managed by the EGR system and related controls, not the ignition signal. Therefore, the spark timing is the aspect the piggyback module is designed to modify.