Fuel Gauge 16gal vs 18.6gal

[Irish Pride]

Last summer my fuel pump went out. I had a spare Walbro 155 lph already and I had been wanting to upgrade from the 16 gal fuel tank to the 18.6 gal tank. I bought the 18.6 tank and the proper sending unit to go with it but ever since I finished the install my gauge has not been exactly precise. It shows full and empty like it should but when it gets to the point that my low fuel light comes on I still have 5 or so gallons in the tank. I can literally drive 100 miles with the light on. I'm wondering if I need to change out the gauge with one from a car that came with the 18.6 gallon tank. Does anybody know if there were separate gauges depending on which sending unit is installed?

 

[zoomlater]

My previous 92 was like that, light on , near the E, but only 13 gallons went in. My current 92 shows 1/4 tank more than what is in the tank, looks great until you fill up and more goes in than you think

 

[Toolman]

I had an 18.6 tank and had the exact results. 5 gal left in tank when light came on. Has taken me years to cure myself of that, as very few others cars let you drive so far with the light on.

 

[rubydist]

that is typical of how Ford fuel gauges work on pretty much all of their stuff.

 

[sperold]

When I had a 120 mile round trip commute, I was filling up pretty often.
After a few months of this, I started carrying a full plastic gas can in the trunk on my low fuel days , as I was starting to run longer and longer into that "gas light on" zone.
My nerve would only last so long; I never had to put in more than 15 gallons, and my car had the large tank.

I don't think there are different gauges for different tanks. I don't know where those 2 1/2 extra gallons come from, but it may not be in depth. I do know that the 18.6 gallon tank is a bear to install and everything has to be perfect to get those 2 straps started. Maybe the little tank goes in easier as the width doesn't play so much of a role.

 

[AREA 91]

5 gallons left when the light comes on.
This is normal.