What indicates a healthy injector spray pattern?

• A. Unidirectional spray
• B. Symmetrical spray
• C. Asymmetrical spray with droplets
• D. No spray

Answer: (B)

A healthy injector spray pattern shows a fine, evenly distributed mist that forms a symmetric cone around the nozzle. This symmetry ensures fuel is atomized uniformly and spreads evenly in the intake port, producing a consistent air-fuel mixture. That uniform mixing leads to smooth idling, good engine response, and lower emissions because combustion stays complete.

If the spray is unidirectional, fuel is aimed in one direction and misses parts of the chamber, causing uneven mixing and potential misfires or hotspots. An asymmetrical spray with droplets indicates poor atomization—some fuel remains as larger droplets, delaying ignition and increasing deposits or incomplete combustion. No spray means the injector isn’t delivering fuel at all, which clearly isn’t healthy.