🔍 Key Concepts

• Fuel injection pump discharge pressure and what directly affects it inside the injector system • Difference between flow restriction (blocked passage) and leakage (loss of pressure) • How plunger stroke and engine load relate to fuel quantity vs. fuel pressure

💭 Think About

• Ask yourself: which option would tend to TRAP fuel and prevent it from escaping quickly, causing pressure to rise in the injection line? • Which option would most likely LOWER pressure by allowing fuel to escape instead of building up? • Does engine load change the pump’s mechanical discharge pressure directly, or mainly the amount and timing of injected fuel?

✅ Before You Answer

• Identify which component failure acts like a restriction (like partially closing a valve) versus a leak (like opening a drain). • Consider whether a longer plunger stroke always means higher discharge pressure, or mainly more fuel delivery volume. • Think about how a plugged spray hole would affect pressure in the line just before the injector nozzle opens.