How do you check a fuel injector's spray pattern?

• A. Measure injector coil resistance with a multimeter
• B. Remove the fuel rail and observe spray with a safe test setup, looking for symmetrical spray
• C. Listen for injector clicking with the engine idling
• D. Replace injector without diagnosis

Answer: (B)

The main idea is to verify that the injector is atomizing and distributing fuel evenly into the engine, which is reflected in a proper spray pattern. The best way to check this is to remove the fuel rail and, using a safe test setup, energize each injector while you observe the spray from the nozzle. A symmetrical, fine mist or cone-shaped spray indicates good atomization and even distribution to the cylinder. Irregular spray, dripping, or an off-center pattern signals issues such as nozzle clogging, wear, or a leaking injector, which can lead to uneven fueling and poor combustion. Electrical tests like measuring coil resistance only confirm the circuit is intact, not how the fuel is sprayed, and listening for a click only tells you the injector is opening, not the spray quality. Replacing the injector without checking the spray pattern wastes time and may mask the real issue if the pattern is still correct.