🔍 Key Concepts

• How a fuel injection nozzle is supposed to seal at the valve seat when closed • What happens if the sealing surface is held slightly open by dirt or debris • Difference between long‑term damage (erosion/cratering) and immediate symptoms like leakage or mis-spray

💭 Think About

• Think about whether dirt on the seat makes the nozzle pass more fuel, less fuel, or fuel at the wrong time • Ask yourself if the effect would be seen only when injecting, or also when the nozzle is supposed to be completely closed • Consider which option describes a direct, immediate consequence of a poor seal at the seat, versus a secondary effect that might happen much later

✅ Before You Answer

• Focus on the word seat – this is the sealing surface that keeps fuel from passing when closed • Decide whether a bad seal would cause continuous leakage or restriction of flow • Check which answer choice describes fuel escaping when it is not supposed to, both before and after the main injection event