diy mpg gauge

[itjstagame]

Originally Posted by sonyhome

itjstagame :

With this gizmo you could have what you want. It's just a matter of programming.

I've already done some of the programming. Java was new to me too but not that hard to pickup. I added a way to 'guess' VSS pulses based on tire size and final gear and a way to calibrate vss pulses over a given number of miles.

I'm also trying to add the cid and crr calculations but stopped at trying to figure out how to use the actual temp, pressure and humidity to get air pressure index. Also I didn't want to release anything until I could get it installed and calibrated (and debugged!) in my truck, but I'm kind of scared to throw a resistor in line with the negative on my injector and can't find my VSS (tons of wires to my trans and transfer case and not sure what I need). For now I'm just using small tankfuls and trying to drive (I have no time to work on most these things anyway).

A graph might be nice but I think I'd rather see a more 'gauge' like interface (with a needle). The only other diagnostic I'd like to add is instantaneous HP/power and keep track of that over trips too.

For instance the same trip done at 45MPH and at 75MPH, the 75MPH will neccisarily have to have generated more energy/hp and most likely used more fuel.

I was also wondering about trying to find a pinout diagram of my ecu and pull signals there. Not the processed signals from an ODB connector, but the actual inputs to the ECU and bridging them.