How accurate is miles left in the tank?

[MetalsGeek]

It's my unproven impression that the gages in the Maverick are digital, and use some sort of technology like a stepper motor that provides precise control of the needle position. The tank sensor could also be digital, but even if not, calibration of an analog sensor with the shape of the tank could be easily done in software. While reading the tank gage is somewhat subjective, I've logged this as "% full" at each fill-up and attempted to calculate gage accuracy in addition to the usual MPG. At this point, it's looking like the error is really small, averaging less than 2% of measured, and never above 8%. So... I think this gage is the best I've ever seen in an automotive application, and miles-to-empty is not too far off. Can't say whether there's a hidden reserve beyond that 13.8 gal rating, though.

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[James K]

I was always curious as to why they said don't let your tank get too low. My father always used to just tell me keep it above half. Never knew why, just figured he was probably smarter than I was so i never questioned it.

A lot of the particulate that is in your tank is heavier than the gas and settles to the bottom. When your tank is low and you shake the fuel up (which happens when you drive) you end up with a greater concentration of particulate. A overly simplified example would be 100 particles in a 10 gallon tank means 10 particles per gallon when full. Run that tank down to the last gallon and you have 100 particles per gallon. There's other factors that can impact this scenario, but when you run a tank down, the last of your tank is dirtier. Generally not a big deal if it's occasional, but constantly doing so will likely impact your fuel systems efficiency.

 

[Gray Goose]

One reason was dirt in bottom of tank, because of dirt in gas station tank, and not greatly sealed fuel systems.

Your comment brought back memories of when the farm bulk fuel tank was near empty and my brother and I tipped it thinking we'd get a couple more gallons to fill the tractor tank. Dad was not happy with all the rust in the glass sediment bowl that he had to keep stopping to empty. Never did that again. Good thing we didn't do that to a modern vehicle. Probably require a tow, a new fuel tank and fuel pump. The gravity flow fuel systems of old were very forgiving.

 

[EJRSSF]

I thought the space in a near empty tank would be filled with humid air. At night it would cool and water would form in the gasoline.

 

[Tom 71 Maverick 24]

I ran my 2013 escape down to 0 and then filled it up. IIRC, the fill-up was about 1/2 gallon short of the advertised capacity of the tank.

Probably won't do that deliberately again, but it was one of those opportunities and I really wanted to know.

 

[Dochatley]

Just stick a 2 gal can of gas in the back of the truck and drive. You can run it to 0 miles left or keep going till it quits. That should answer all questions you have about it.

 

[Charlie950]

For what it's worth ... with about 2500 miles on our/wife's Lariat, I had the 0 MILES left in tank message pop up. Sadly I was driving a country-ish road I hadn't been on for some time and had just past gas/convenient store. I went into "hyper-hyper" mileage mode but tried to maintain the 35 MPH speed limit tho' traffic was not too bad. I went another 5 miles or so to the next gas stop. Didn't fill-up so not sure exactly where the tanks was it empty-wise.

 

[HeyBales]

I thought the space in a near empty tank would be filled with humid air. At night it would cool and water would form in the gasoline.

The sealed nature of fuel systems for years means it's always given a slight vacuum, the air pulled out with fumes is run through the Evap system to burn.
My 2005 Rav4 gives that suck whoosh when fuel cap removed. Several vehicles thru the years it's noticeable.

A glass with cold water in it put into a warmer humid environment condensates on the outside.

But you'd need a very specific scenario where your warm tank is put into a very cold environment to equal that sort of change.

Normally your whole truck, fuel tank and air inside, is dropping temp right along with the outside air.
Any slight delay to air temp change on the other side of the fuel tank material is going to be minuscule for amount of slight vacuum induced air moisture that could condensate out.

These are just not the ancient vehicles of the past that lead to those issues. Well - unless you have a current issues - like check engine light on and a code regarding an Evap leak somewhere on the wrong side of a valve.

 

[MakinDoForNow]

Can't say how accurate, since I haven't run out, yet. However, the manual states (for the hybrids) that if you do run out, you need to put in 1.5 gallons before trying to restart it. The number of gallons I have put in it at fill-ups seems to agree with a 13.5 gallon tank combined with the miles driven.
So, advice for hybrid owners is to never let distance to empty get below 60 miles (1.5 gal @40 mpg)

1.5 gallons will register 0 remaining miles on the miles remaining! The 0 means that you should add gas as the 1.5 gallons is the recommended amount in tank. In any case I normally fill up at 80-100 miles remaining!

 

[colinl]

Best advice I can give is to not let your tank even get that low. Makes your fuel pump work harder.

most of the replies here are hybrid owners.

ecoboost owners should not run on low fuel because high pressure fuel pumps are very intolerant of fuel starvation. they very quickly overheat and fatigue, and then die abruptly even after low fuel isn't an issue.

it's been happening to broncos because it's relatively easy to starve the pump when crawling with less than a third tank or so. you can definitely do it cornering hard in any vehicle with very low fuel.

 

[CometGT]

1.5 gallons will register 0 remaining miles on the miles remaining! The 0 means that you should add gas as the 1.5 gallons is the recommended amount in tank. In any case I normally fill up at 80-100 miles remaining!

Actually, on mine 0 DTE will have 0 gallons. Had 90 DTE and it took 11.5 gallons.
90 / 40 mpg =2.25 gal 11.5 + 2.25 = 13.75 which is the tank size....
BTW: the (observed) 5% better gas mileage using 91 octane (as the manual recommends) is still holding true.

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