🔍 Key Concepts

• Jerk-type fuel injection pump operation cycle (suction, pumping, cutoff) • Flow path of fuel from the plunger to the injector nozzle and back toward the pump • What happens to pressure and nozzle needle movement at the end of injection

💭 Think About

• Think about which component actually stops fuel injection: is it mainly the plunger/helix, the injector nozzle, or the delivery check valve? • Ask yourself what would happen inside the high‑pressure fuel line and injector if there were no delivery check valve at the end of the pump stroke. • Consider which option best explains how the system avoids dribbling or secondary injection after the main shot of fuel.

✅ Before You Answer

• Verify which part controls start and end of injection in a jerk pump (plunger vs. check valve vs. injector). • Check which function would prevent pressure from dropping too slowly in the injection line after the pump stroke. • Eliminate any choice that describes a function already performed by the plunger helix (fuel metering and spill‑back).