After maintenance, what validates a successful purge of air from the fuel system?

• A. No air pockets and continuous fuel flow
• B. Fuel smell in the cabin
• C. Engine warms up quickly
• D. Battery voltage stable

Answer: (A)

Purging air from the fuel system is about filling the lines with fuel and removing all air pockets so fuel can flow to the engine without interruption. After the purge, you validate it by seeing a steady, continuous fuel flow with no air pockets in the lines—think of a constant, bubble-free stream during priming and normal fuel pressure when the engine cranks. This ensures the engine will start and run smoothly without misfires caused by air in the line. Signs like a fuel smell in the cabin suggest leaks or spills, not a successful purge, while engine warm-up speed and battery voltage don’t directly indicate the purge outcome. So, no air pockets and continuous fuel flow best confirm a successful purge.