What is a common sign of injector leakage that can be observed during a pressure test?

• A. No change in system pressure.
• B. Fuel odor around injector and measurable leakage.
• C. Increased oil pressure.
• D. Coolant leak.

Answer: (B)

During a fuel system pressure test, injectors are expected to seal tightly. A common sign of injector leakage is fuel escaping around the injector itself, which you can detect as a strong fuel odor and visible or measurable leakage at the injector area. This indicates the seals or the nozzle are not holding pressure, allowing fuel to seep out when the system is pressurized.

Why this is the best answer: the test pressurizes the fuel rail and lines to reveal any paths where fuel can escape. Olfactory detection of fuel and a measurable leak are direct indications that the injector is not sealing properly, which can impact fuel delivery, engine performance, and safety.

In contrast, no change in system pressure would suggest the opposite—that there’s no leak. Increased oil pressure and a coolant leak point to issues in other systems (oil or cooling), not injector leakage in the fuel rail.