Can anyone explain to me why, even on a seemingly empty tank, I can't squeeze more than 14 gallons of fuel into a tank that Acura defines as 17.1 gal?

I have the same issue on my 06 TSX as well.

Lots of threads on this. Do a search for more info, but it seems the miles to go is programmed to read zero when there is approx 3 gal left in the tank. Most folks assume Acura did this to avoid fuel pump overheat issues. I wouldn't worry about it, it's best not to let the fuel pump run dry or be uncovered, which will never happen if you fill up according to the MID.

Here are some answers:
https://acurazine.com/forums/3g-tl-2004-2008-93/fuel-tank-capacity-733161/
https://acurazine.com/forums/3g-tl-2004-2008-93/gas-light-miles-left-726363/
https://acurazine.com/forums/3g-tl-2004-2008-93/gas-guage-accuracy-556650/
https://acurazine.com/forums/3g-tl-2004-2008-93/fuel-tank-capacity-04-a-693813/
https://acurazine.com/forums/showthr...d.php?t=629777
https://acurazine.com/forums/3g-tl-2004-2008-93/17-1-gallon-tank-629286/
https://acurazine.com/forums/showthr...d.php?t=746669

my gen2 has a low fuel light that comes on at 3 gallons remaining of 17.a little capacity (average 14.5 fill when I get to station)
that gives you a good 50 miles to find your brand of gas!!
Most I ever put in with guage well below empty was 16.7

It does prevent contamination of the fuel sock (filter) from possible crud on bottem of tank and overheating of the fuel pump, plus you never want to run an injected car dry- really hard on parts overall

When it says time to fill- sometime that day or the next would be a good plan to fill up again

Your owner manual is filled with all sorts of info like this

Welcome! The posts before mine have answered your question pretty fully. The fuel capacity is 17.1 gallons for our car, but the fuel light comes on with about 3 gallons of fuel left in the tank.

in the trip computer, it will tell you the range you have left, plus after that runs to 0, I think you get another 20 miles +/-. I vaguely recall a thread where people were testing that absolute range out.

2.5 gallons x miles at your typical mpg is your absolute range after zero
or Low indication example 300 to zero, 20mpg avg,= 50 miles to empty= 350 total
On trips it can be much higher