Now, the specialist magazine Racecar Engineering reports in its latest issue that an alternative sensor "is in the final stages of development", and could even make its debut later in 2014.
The new sensor is reportedly being developed by a company called Sentronics, with the involvement of Hyspeed, who initially worked with Gill on the current F1 sensor.
The Gill-Hyspeed collaboration, however, ended last year, leaving Hyspeed to start work on the new solution.
"We remain convinced that the ultrasonic time-of-flight principle is the best way of measuring fuel flow on board a race car," said managing director Neville Meech, who formerly worked for Gill.
He said the Sentronics sensor, called the 'Flowsonic', is a "compact and robust unit with the minimum of materials and parts, and hence less to go wrong".
It also weighs just 250 grams, half the maximum permitted by the FIA, Racecar Engineering added.