I installed an Ultra Gauge display unit that plugs into the OBDII port on the Ford E450. As we know, the current E450 dash is lacking on info like distance to empty, average mpg, etc. Well, all that stuff is in the ECM, but it’s just not displayed anywhere. The Ultra Gauge (and there are many others devices like it) will display about 60 parameters from the OBDII port in real time while you’re driving, like ambient air temperature, engine temperature, average and instantaneous MPG, trip data, etc. How this applies to this thread topic is that it will display fuel level remaining in gallons. So right now my E450 says there’s 49.7 gallons of fuel remaining. I think the ECM reads it out in percent but the Ultra Gauge converts it to gallons because you configure it with your fuel tank capacity.
We’ll soon be taking a trip to test this device out, but I think it will be useful in tracking fuel level, usage, and distance remaining on a tank.
I am not affiliated with this vendor, rather I’m just a customer. Here is a link to the product page:
http://www.ultra-gauge.com/ultragauge/