Fuel Gauge question

[joesho_gb]

Yes, it's me again. Anywho, I ran the car to Minneapolis this past week, and noticed that I only made it about 215 miles on a tank (before the fuel light came on).
Thought this was a bit odd, then when I filled the tank up, it topped off at about 10.5 gallons. Thought to myself was "wow, small tank!". After starting it up, the fuel gauge showed a little over 3/4 full, even though the tank topped off.

Then curiosity got the best of me, and I looked into the owners manual, and according to that, the SHO should have an 18.x gallon tank.

This is a dumb question, but is possible that someone changed the tank to a smaller one (the one that comes with the 4 cyl Taurus is an 11 gal tank), or is my gas gauge screwed up?

 

[Shoaz]

Has the fuel gauge ever made it to full before? It could be that the filler nozzle just hiccupped and you stopped before the tank was full.

 

[joesho_gb]

I just bought the car a week ago. The highest I have ever gotten it was a tad above 3/4.

I thought the same thing (the hiccup), but I had to fill it at least 4 times (all around the 200 - 250 range), all with the same result.

I'm wondering if the fuel float isn't stuck. Going to throw a gas can in the trunk and drive it until it stalls, then I'll know if it's the 11 gallon tank, or the float.

 

[geomarathoner]

The early SHO fuel gauges are notorious for strange readings. Mine has always read waaay high until the tank gets under half-full. After a fillup I always reset the trip odo. The gauge will stay above "F" until about 250 miles. Then it starts to drop pretty rapidly and it gets to just over the "E" and the light comes on. At that point I usually refill and it takes 16+ gallons....the trip odo is usually around 350+ unless I'm on a highway drive and it'll be 400+. So it seems to be accurate near the bottom of the 18 gallon tank but worthless above that.