At the end of an injection cycle on an engine equipped with a time pressure fuel system which of the following should be true?

• A. Nozzle spring closes fueling plunger
• B. TP tappet spring closes cup orifice
• C. Moving components of the injector are loaded into the cup with mechanical crush
• D. The cup remains open and exposed to cylinder gas pressure

Answer: (C)

In a time-pressure fuel system, the end of an injection cycle is managed by seating and preloading the injector’s moving parts inside the control cup. This is done by mechanically crushing the cup around those components, which creates the correct preload and locks the parts in place for the next cycle. This preload and seating stop further movement when the cycle ends and prevent leakage as cylinder pressure fluctuates.

Why this is the best fit: loading the moving components into the cup with mechanical crush ensures the injector is reset with the proper clearances and preload, ready for the next injection event. The other mechanisms described don’t match how a time-pressure system terminates an injection; springs acting on the nozzle or cup, or leaving the cup exposed to cylinder pressure, would not reliably reset or seal the metering chamber for the next cycle.