🔍 Key Concepts

• Fuel system suction vs. pressure sides and how air is most likely to enter • Typical flow path of diesel fuel from tank to engine (suction → filters → pumps → injectors) • Difference between leaks that draw air in and leaks that spray fuel out

💭 Think About

• Think about which part of the fuel system operates under vacuum (suction) instead of pressure. • Ask yourself: where can a small opening let air be sucked in without necessarily showing a visible fuel leak? • Consider the sequence of components: if air is entering early in the system, where would it cause misfiring across multiple cylinders?

✅ Before You Answer

• Identify which choices are on the suction side of the system vs. the high-pressure side. • Consider whether a leak at each option would more likely spray fuel out or pull air in. • Verify which location would affect all cylinders rather than just one or two.