Abstract: A vehicular fuel flow measuring system derives a value for the consumption of fuel by an internal combustion engine operated with fuel from a tank containing a source thereof. The engine has a fuel introduction system with a first fuel pump having a suction input and a discharge output. The discharge output is coupled in fuel supply relationship with the engine for carrying out fuel combustion and recirculation functions. The fuel introduction system includes a first return conduit carrying return fuel for the recirculation function. The first return conduit has a first pressure regulating relief valve disposed therein. A second fuel pump is connectible between the first fuel pump and the fuel rail of the engine. The second fuel pump has a suction inlet and a discharge outlet for discharging pressurized fuel to the fuel rail of the engine. At least one flow measuring meter is connectible between the first fuel pump and the fuel rail of the engine.