Why don't we all have MPG readouts?

[captainslug]

Because I don't have a car.
My fuel efficiency is phenomenal!

[aalb1]

Originally Posted by Ryland

I'm pretty sure that the dual fuel injector set up is mostly a "cold start" injector and a "normal" one, the cold start one is used instead of a choke to allow a simpler control set up of the engine, some MPFI systems used a 5th injector like this as well, as seen on older Toyota's.

Not just a cold start injector... it's an auxiliary injector. Hooking it up to my dwell meter it's always on. In fact it is the injector that keeps the car running during idle while the main injector shuts off.

Originally Posted by MetroMPG

Or, assuming both injectors operate at stoich, you could make an instrument that extrapolates MPG based on air flow like the ScanGauge does.

Any ideas on how to measure airflow?