Fuel quality sensor associated with a housing in fuel delivery system

An apparatus 10 monitors at least one fuel quality characteristic of fuel passing through a fuel delivery system 12 of a motor vehicle. The apparatus 10 includes a fuel rail assembly 18 connectable to the fuel delivery system 12 of the motor vehicle. A fuel rail assembly 18 has at least one housing 14 associated with either a pressure regulator or an accumulator. A sensor is associated with the fuel rail assembly 18 for measuring at least one characteristic of fuel quality of fuel passing through the fuel rail assembly 18 . At least one characteristic includes temperature and/or impedance. The sensor 16 can include a pair of plates 20, 22 spaced from one another by a gap of between approximately 0.5 mm to approximately 1.0 mm, inclusive, for measuring impedance across the gap.