🔍 Key Concepts

• Diesel engine ignition (compression ignition vs. spark ignition) • What happens to a fuel system when filters are changed • Effects of air in fuel lines on engine starting

💭 Think About

• Ask yourself: right after fuel filters are replaced, what part of the engine system was disturbed the most—compression, fuel, or ignition? • Which of these answer choices would appear suddenly after maintenance, rather than being a long‑term wear or design issue? • Which type of engine actually uses spark, and which one relies on fuel being injected into high‑pressure, high‑temperature air?

✅ Before You Answer

• Verify which answers involve diesel-specific systems rather than gasoline systems. • Consider whether air must be bled from the fuel system after opening it to change filters. • Ask: which option would most directly prevent fuel from reaching the injectors immediately after filter replacement?