Fuel Capacity and Range and MPG readings

[KenDude]

Today I filled up my car after letting it run down to where the miles left showed - - -. At 39 miles left the Nav system came up and asked me if I wanted to find a gas station and showed the closest ones. (Nice feature) and I continued to drive because I wanted to get to a certain mileage mark. At about 30 miles left the display changed to miles left - - -, which I don't particularly car for but I understand they want to prompt you to stop and get gas so you don't run out and they try to provide a margin of error. (our old Lexus we could drive down to zero and still have range). So I drove another 15 miles before stopping to get gas. I assume I had somewher around 15-20 miles of range left.

I stop and fill up at a station that is 100% gasoline, no ethanol. To my surprise the pump clicks off at 14.5 gallons. I squeeze the handle again and get to 14.63 before it shuts off again. I can hear fuel and I don't want to slosh it out so I stop filling at this point. When I start the car it shows the gas gauge as full but of course has no MPG rating yet. As we drive that climbs up to around 30 because we immediately got on the highway and I was doing between 65 and 70 keeping an even speed on cruise. Also my surprise it says my range is 315 miles, yet my avg mpg is showing up as 30 on the meter on the dash. That would mean I'd have just over a 10 gallon gas tank, something isn't right with that figure.

Ok, so granted someone's meter math who designed the electronics for the Santa Fe isn't as good as it could be (adjusting on the fly for current mpg and remaining volume to calculate range), I'm still baffled by the amount of fuel I could put into the tank. I was basically 3 gallons short of full, and at even 21mpg (city rating for FWD 2.0T) that would be another 60+ miles I could have driven so why the early warnings, inaccurate miles left reading and --- getting near the end?

One of the following has to be true:

1) The calculations and electronic display are VASTLY inaccurate

2) We don't have a 17.4 gallon tank, maybe 15.4 in which case the advertised range of this vehicle is significantly less than advertised.

Using this topic thread, let's keep track of how much fuel you are able to put into your santa fe sport at fill up. Please record how many miles you drove on that tank, what your miles remaining reading showed on the dash, and how much you put into the tank. Here's mine:

A] 287 miles (artificially low due to lots of idling to show car to people)
B] ---
C] 14.63 gallons

For those who don't know, I've attached the mpg ratings and fuel capacity for the different Santa Fe Sport versions as shown on Hyundai's website.

Something just isn't adding up with the mpg and capacity of the new Santa Fe and hopefully by gathering data we can figure out what it is. Given some simple math the range of my Santa Fe FWD 2.0T should be between (21*17.4= 365.4 miles and 31*17.4= 539.4 miles) If you just take the avg of 25mpg that would be a range of 25*17.4=435 miles.

If you assume you drive a car 1 gallon is left, it would be 25*16.4 = 410 miles. Why does my car say I have 315 miles left after a fill up? I wouldn't be happy with 25% less range than advertised!

(For a moment let's assume Hyundai made a mistake and the gas tank is really a 15.4 gallon tank, not 17.4, then assuming you drive until 1 gallon is left you'd fill up at around 14.4 gallons [close to where I filled up] in which case you'd have 14.4*25 as your "average" range or 360 miles which is still further than what I'm getting and what the display says... 14.4 x 21 = 302.4 miles, in essence pretty close to what the range says, so basically taking a smaller tank and the worst mpg rating is the only way I can get down to what the real world numbers seem to be, but I'm hoping to get more real world numbers from the rest of you.)

Can a Moderator / Admin make this a sticky topic thread?

[neogenesus]

The range change over a preiod of time. The car's computer learn how you drive and then based that on the RTE readout. Also the RTE reading is a little bit conservative as you can drive 30-40 miles after the RTE start to go blank ---- like that. Hope that helps.

[Zoom49]

I don't have a 13 Sport but a 09 Santa Fe. We can typically safely drive another 90 miles after the gage goes to ---.
Hyundai calculated the miles remaining very conservatively. Also the range is based upon an average of the last two fill-ups, not the current fuel usage.
Ours also tends to underestimate the potential range. We needed three consecutive highway trips with ours to get a range over 400.

This is how our 09 works and may not be true on the new Sport. Hyundai does not want any lawsuits due to running out of fuel when the dash says 30 miles past ---.
In time some of you will test the excess miles past --- on your vehicles. Until this number is verified, drive with caution.

In my experience Hyundai's average miles per gallon dash display is also on the optimistic side. Mine typically shows 10% higher than the actual calculation method.

[ddauber]

[QUOTE=KenDude;1149869]

A] 287 miles (artificially low due to lots of idling to show car to people)
B] ---
C] 14.63 gallons

QUOTE]

Short trip yesterday...

A] 133.6 miles
B] ---
C] 4.865
D] ~27.5 MPG Calculated
E] 30.1 Dash ReadoutComputer
F] ECO ON
G] Highway 55mph max.

[golfermack]

Originally Posted by KenDude

One of the following has to be true:

1) The calculations and electronic display are VASTLY inaccurate

2) We don't have a 17.4 gallon tank, maybe 15.4 in which case the advertised range of this vehicle is significantly less than advertised.

How about 3 & 4?
3) The pump shuts off with room for 1-2 gallons more.

4) A combination of 1-3.

I'm curious what the answer is. Perhaps some brave soul could drive the car until empty, and then fill up.
John

[ddauber]

Service dept told me this morning that I should expect 6 mpg difference than advertised. Wow! I'm not convinced thats a true statement. Has anyone else heard this before?

[KenDude]

Originally Posted by ddauber

Service dept told me this morning that I should expect 6 mpg difference than advertised. Wow! I'm not convinced thats a true statement. Has anyone else heard this before?

If it is, then that's a lawsuit waiting to happen as the % from advertised would be outside of reasonable expectations. I haven't heard this and so far I'm averaging better mpg on my 2nd tank of gas than my first but that's because I haven't been sitting idling showing people the car, etc. The range / capacity still isn't close to being right though... that's what's concerning me...

[7milesup]

General rule of thumb is you need somewhere around 5000 (five thousand) miles on a vehicle before the mpg starts to peak. I am assuming that no one has that on their SF yet?.....

[KenDude]

Originally Posted by 7milesup

General rule of thumb is you need somewhere around 5000 (five thousand) miles on a vehicle before the mpg starts to peak. I am assuming that no one has that on their SF yet?.....

Actually old wives tale based on old cars with carburetors and iron blocks... today's cars set up within a few hundred miles and are broken in and don't magically get better over time like some older cars would do (I say some because it was really only those that needed more time for rings to seat, seals to firm up, etc. back in the day of points and carb needles needing adjustment, etc.) this old wives tale keeps being pervasive even today despite the abundance of scientific evidence to the contrary...

[rmissourimule]

I wouldn't recommend driving it until it runs out of gas. The fuel pump is lubricated by the fuel and that would be an expensive proposition to replace. The range is obviously very conservative and I'd just use it as a general rule of thumb.