🔍 Key Concepts

• Jerk-type fuel pump construction – relationship between plunger and barrel • Mating / lapped parts in precision fuel injection systems • Effects of wear and clearances on high‑pressure fuel sealing and timing

💭 Think About

• Which component in the list works as a precision, tightly-fitted match with the plunger to create very high fuel pressure? • If you install a new plunger into a worn mating part, what happens to leakage, pressure, and timing accuracy? • Among the listed parts, which one is normally ‘lapped’ or matched as a set with the plunger in manufacturer service procedures?

✅ Before You Answer

• Identify which part forms the high‑pressure pumping chamber together with the plunger. • Ask yourself which part typically comes as a matched pair with the plunger in fuel pump overhaul kits. • Confirm which items on the list are more likely to be separate, reusable components (valves, tubing, followers) rather than precision-matched to a specific plunger.