A fuel delivery system for a vehicle having an engine includes a fuel injection system, a fuel supply line configured to supply fuel from to the fuel injection system, and a fuel pressure sensor. An active expansion chamber (AEC) accumulator is fluidly coupled to the fuel supply line and includes a housing defining an interior chamber and an adjustable expansion chamber, a plunger assembly separating the interior chamber and the adjustable expansion chamber, and an actuator configured to selectively move the plunger assembly to actively adjust a volume of the adjustable expansion chamber. A controller is configured to detect a pressure change condition in the fuel delivery system and, in response, automatically adjust the volume of the adjustable expansion chamber to maintain the pressure of the fuel delivery system below a predetermined threshold to thereby facilitate preventing fuel leakage at the fuel injectors when the engine is shut off.