I can't seem to find the size of the gas tank in my manual. My salesman said it was supposed to be 15 gals. I haven't put any more than 13 in when the gage said 10 miles left. I am going to start a record of how much the gage (is this the right word?) says it should get for the tank when I fill it (around 400 plus) and record as it goes down. It does not go down relative to the actual mileage. It jumps down from time to time. I haven't figured out what is going on. I have not gotten more than about 323 miles to a tank, filling it at 13 gallons.

aloha,
mehitibel

 

Fuel Data FWD

Fuel
Fuel Tank Capacity: 15 gal.
EPA Mileage Estimates: (City/Highway)
Automatic: : 36 mpg / 31 mpg
Range in Miles: (City/Highway)
Automatic: 540 mi. / 465 mi.

 

A lot of these hybrids seem to have an overly pessimistic guess gage. My thinking is that they are trying to minimize the frequency of vehicles running out of gas to give them extended life, so when a person wants to use the full capacity of the tank they have to test and see what it really is. I guess you can look at it similarly to the way the battery gets treated, never less than 40% charged to increase it's life.

 

I also believe it guesses based on your FE, so as your MPGs go up, so does the miles to empty, and as your MPGs go down, so does your miles to empty.

Also, I believe as it gets broken in, it increases. My average when I fill up is 477 miles to empty now, compared to 440 when I first got it, which is what I think it figures will burn 13 gallons of gas, leaving you with plenty even after you hit zero to empty.

 

I got mine down to "2 miles to empty" and it took 13.6 gallons to fill it so I agree that they are being conservative to help avoid running out. I still had better than 40 miles worth of fuel before true empty.

 

Most cars today have pretty inaccurate fuel gauges. In fact the manual states the indicator is an "approximate" fuel indicator level...so they really are not trying that hard.

It's generally a bad idea to run to empty anyway...

It is true that it's harder to fill a hybrid's tank "really full" due to the evaporative controls which are much more involved (bladder or advanced vapor recovery system depending on the model) than in a conventional car.

 

The automakers care about 2 things when it comes to fuel guages:

1) The guage should not be reading above empty when the actual fuel level in the tank is at empty (i.e. don't give the driver the false sense that there is gas in the tank when there really isn't)

2) The guage should read full when the tank is actually full.

All bets are off for everything else in between. They often continue to read full when they're only maybe 85% full (I used to have a car that still read full when I knew it was at 3/4 tank) -- and they often read empty when there's 2-3 gallons left, in fact they prefer it. This is not considered to be a defect.

It's just not a good idea to try to completely empty a tank before refilling it.

 

I know my Chevy Colorado was only really accurate around the 1/2 full range. It took forever to move off full and dropped like a rock below 1/4. I learned early on to calculate the actual fuel level based on miles driven since filling the tank.

 

There's been some talk about the FEH gas tank in the past...can't remember if it was here or the Yahoo group. Long story short, the FEH (like all the Ford's I have ever had), has a 1-2 gal safety margin with regards to the gas tank. In other words, when you think the tank is absolutely empty (according to the gauge/Msg ctr/Nav) you usually have about a gallon left. I've taken my FEH down to near 0 DTE and never filled beyond 13.5 gal. (To look at the gas gauge pointed at E...you'd think I was running on fumes!) My '01 gas escape was the same way...it would scare me into getting gas with the needle pegged on E...with 1-2 gal left!!

With that said, there are a few people who have actually run out of gas in an FEh. They report the actual "useable" portion of the fuel (due to design) is about 14.5 gal--even though the capacity is 15 gal according to Ford. So, I shoot for getting gas right at the 0 mi DTE. That gives me, in my view, 25-30mi safety margin. Hypermilers probably get a bit more margin....I avg 29 mpg.

**Again, this is just what I've read and experienced. I'm NOT an auto engineer by any stretch of the imagination. Experiment at your own risk.

Nate

 

On the almost extreme end of 'safety magin' the HAH gage goes to E and the idiot light comes on with ~4gal left! 13gal through a 17gal tank.