Hi Nuno:

If you have a car with a injection, the best sensor is a car computer
itself. I am close to finish the computer that you mentioned  and all
signals that I needed I have found on a car computer. I do the computer
for my Ford Escort with the central injection. The frequency of pulses
to the injection valve is more or less (it depends of temperature,
pressure of petrol, etc.) equal a small quantity of petrol. I did some
measurement and I am certain that it would be enough accurate for your
purpose.

Let me know if you are interested about my solution. I built a car
computer with PIC16F84.

The best sensor, used with car computers for measurment a consumption is
a heated wire with two thermistors (very small of course) in a way of
petrol. You heat a wire with pulses and measure the resistance of both
thermistor - basicaly you measure how much time a hotter petrol needs
for a distance between thermistors. I think that one thermistor only
could serve well too.

Regards

Igor

> Hi there!
>
>   WITHOUT going way OT like in that injection discussion, I would like
> to know if someone has used some kind of sensor to measure fuel flow.
>   The idea is to measure the instantaneous fuel consuption. Problem is
> that it's a small flow. If cars spent more fuel, it would be a lot
> easier! 8)
>   Why am I here?
>   Well, I want to build a small car-computer, based on PIC. I really
> would like to include fuel consuption indication on its features.
>
>   Thanx,
>
> Nuno Pedrosa.