🔍 Key Concepts

• diesel fuel system components such as pumps, injectors, and filters • how solid particles in fuel affect high‑pressure, close‑tolerance parts • difference between fuel system problems and air intake problems

💭 Think About

• Which component in a diesel engine operates at very high pressure with extremely fine clearances and would be most vulnerable to tiny hard particles? • Do transfer pumps normally have some tolerance for small amounts of contamination, or are the most critical parts usually further downstream? • Which option talks about something that is not in the fuel system at all but in a different system of the engine?

✅ Before You Answer

• Eliminate any choice that deals with the air system instead of the fuel system. • Focus on the part of the fuel system that has precision-machined, close‑fitting parts working at high pressure. • Ask yourself which failure due to dirt is most commonly emphasized in diesel engine maintenance training and manuals.