Fuel gauge accuracy?

[Garfy]

I just got a low fuel warning on my 2020 GT today saying I have 50 miles to empty. The gauge reads precisely 1/4 tank and it doesn't make sense to me. If it has a 16 gallon tank, 1/4 tank would be 4 gallons (most vehicles also have a small amount of "reserve" even after hitting empty) and my current economy is just over 19 mpg so shouldn't my DTE be 75-80 miles? On my Hondas the low fuel indicator won't come on until I'm at about 1/16 of a tank nearing the red band on the fuel gauge. If it's truly 50 miles DTE then would it mean my gauge would be above the "E" when I run out of fuel? Should I have the dealer check it? It's only got about 1300 miles on it. Thanks!

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[ice445]

It's not just one gas tank, it's got two saddles with a transfer setup to fit around the rear subframe. I suspect that creates some non ideal low fuel shenanigans. No harm in getting it checked though, I never get a low fuel warning at 1/4 and I have worse calculated economy than you do.

 

[ORRadtech]

My DTE never comes on until it's below 1/4 mark.
FWIW I've checked the DTE estimate/ notification on mine and it's pretty close. Close enough I don't push it like I do with my Edge or Fusion. Both of those have 30 miles or so when it says 0 miles. The Mustang is closer to 7 or 8 miles. I only pushed it that far once and definitely won't again.

 

[WD Pro]

I’m more interested in the ‘just over 19 mpg’ ...

I’m just over 15 and that’s a imperial gallon (so about 12.5 US mpg / 18.8 L per 100 km).

Only engine mod is a dry filter.

Who’s closer to the norm here ? Do I need a right foot adjustment ... ?

WD

 

[ModularKid21]

On the way home one day I ended up being lower on fuel than I realized. I was only about 10 miles from home and the fuel light had been on for a little while already. I was feeling kinda lucky and decided to push it. Once the DTE read “0 miles til empty”, I drove another 7 miles until I got to a fuel station and filled up. I can’t remember how much fuel it actually took but I wasn’t “empty”.

Obviously wouldn’t recommend this, and I never let myself get that low on fuel, but just a point of reference from experience

 

[Dfeeds]

The gauge pod is facing up and to the right. It's a little wonky. If you shift your head to be more "dead on" It's lower, at least for me. My 50 miles always comes on at 1/4 from where I sit but if I lean to the right the needle looks to actually be a bit lower.


FWIW, to comment on somene else, I get 19.5 mpg with the frpp kit installed.

 

[Garfy]

It's not just one gas tank, it's got two saddles with a transfer setup to fit around the rear subframe. I suspect that creates some non ideal low fuel shenanigans. No harm in getting it checked though, I never get a low fuel warning at 1/4 and I have worse calculated economy than you do.

OK, thanks. Yes, I recall something about having 2 fuel pumps; one was the "main" pump that supplied the fuel to the engine's fuel rail and the other was a "transfer" pump to move fuel from one side of the tank to the other (I suppose it was due to the driveshaft passing underneath the fuel tank so it straddled the shaft). Funny thing was when I took the car on a test drive before buying it, the fuel gauge was showing almost empty and the DTE was 9 miles. I only drove the car for about 3 miles because I didn't look at the fuel level until I got on the freeway. I guess it must have 2 fuel level sending units then so just to stay safe, I'll contact my dealer.

BTW I am surprised with the fuel economy, but then I haven't punched it much at all during this first 1000 miles. What did surprise me was some Youtube videos I watched, some guy was flogging his GT doing 1/4 mile runs with only 450 miles on the car. I think the manual cautioned against this kind of driving for at least 1000 miles. I also don't drive hard because of my insurance company's "Drive Safe & Save" program which reports how you drive in distance, hard accel and braking as well as hard cornering. Of course, I do turn my phone off when I tried a 0-60 test & probably will when I try my first 1/4 mile run on Trackapps.

 

[Vlad Soare]

I got the low fuel light today, and an 80 km (50 mi) to empty warning. The gauge was at precisely one quarter of the tank.

 

[Bandi]

My car tells me I have low fuel at 50 miles. At times, I will have lower fuel when I get out the car and the fuel needle sometimes goes up a little bit.

I just make sure I don't make the fuel light come on and just drive the car. It's accurate enough where it's not like I think I have a full tank but I'm actually near empty so I don't really worry about it.

 

[Johnnybee]

Never had the low fuel light come on in any car. When we were young my father told us that if we ever had car trouble, day or night, to call and he would come and aid us, unless we ran out of gas, then we were on our own. Consequently, it is rare that I ever fall much below half a tank. Old habits die hard.

 

[Garfy]

Never had the low fuel light come on in any car. When we were young my father told us that if we ever had car trouble, day or night, to call and he would come and aid us, unless we ran out of gas, then we were on our own. Consequently, it is rare that I ever fall much below half a tank. Old habits die hard.

I'm kind of like the same way, usually fill up before it even reaches 1/4 tank, but I'm purging the regular unleaded and refilling with premium in preparation for my acceleration tests. I figured if I did this a few times, that would pretty much get rid of any regular unleaded left in the tank.

My main reason for keeping the tank above 1/4 is that the fuel pumps are cooled not only by the fuel moving through it but also the fuel surrounding the pump. If the tank is low, the pump is not immersed in the gasoline which will cause it to run hotter than if it were submerged. I've replaced many fuel pumps from people who never fill their tanks to full, always running at low levels because they can't afford to do so. Funny that they have money to replace the pump when it fails (I found that pump failures were far more common in domestic cars than on Honda or Toyota).

Since others have seen the low fuel indicator come on at 1/4 tank or near it I guess mine is "normal". Different car, different system.

 

[Zathras]

My 50-mile-warning comes on at about 1/4 tank on the gauge (analog version), but since I get about 15 mpg in my typical driving it seems reasonable. I think there is a little "extra" range in the distance-to-empty calculation, but possibly not a lot. As other posters already noted, it's hard to be precise when reading the gauge, because it's off to the right and the apparent position of the needle changes depending on whether you look at it with your head in the driving position, or if you look at the gauge head-on.

Personally I would prefer that the the "low fuel" warning be adjustable. If I could set it myself, I'd set it to come on at 25 or 30 miles to empty rather than 50.

 

[Mike Pfeifer]

The gauge pod is facing up and to the right. It's a little wonky. If you shift your head to be more "dead on" It's lower, at least for me. My 50 miles always comes on at 1/4 from where I sit but if I lean to the right the needle looks to actually be a bit lower.


FWIW, to comment on somene else, I get 19.5 mpg with the frpp kit installed.

It’s interesting to see this posted here as I was just getting ready to ask about it. I have had my Mustang for about a month now and have been looking at that fuel gauge with suspicion. It seems to me like the needle is off center and was wondering if others were the same way. This is a pic with the fuel gauge at 1/2 and it clearly doesn’t line up with the marking. For it to point at the marking, the needle actually needs to be closer to 3/8.

 

[Garfy]

This is what my gauge looks like straight on; the needle is clearly at the 1/4 tank position and DTE is now showing 48 miles. But I won't take it in to the dealer as it seems that others have similar DTE and fuel level readings.

 

[gadgtfreek]

Yep mine is usually around 50 miles to go when the light comes on, then I hit the Costco. It generally takes 11-12 gallons.

17mpgx4 gallons means it sand bags a little, but almost all new cars do that. How many people you know, especially wives, that ride that counter to almost zero?

Fun MPG fact. Me and some buddies took a road trip, two cars. The Stang got almost the same MPG as a 2015 V6 explorer. Not bad.

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