Fuel Remaining Incorrect

[ACAD_Cowboy]

Well the pump shut off is triggered by back pressure from outflowing vapors and or liquid.

As for your phantom 3 gallons, yeah it's possible. I've never been feeling bored enough to pull the tank, drain it dry, blot it and then go through a hand fill so I honestly have no idea how much physical capacity the tank has versus working capacity. The shape is very convoluted with a bunch of weird projections etc. Just fill it until the pump clicks and be happy you can afford the guzz'aline.

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[ShadowsPapa]

I recently filled up when the "Low" light should have come on (15mi remaining) but it did not. Put in 19gal in my tank. So I either had 3gal of fuel left when I filled up, or like above was stated, the sensor for the cutoff is situated such that it leaves 3gal space in the tank for gas expansion.

There's nothing in the tank that shuts off the nozzle. The nozzle has no clue how much is in the tank or how much space is left. Imagine filling my 5 gallon gas cans - the nozzle shuts off when the fuel level is close enough to the nozzle to trigger it (vapor or fluid splash, etc.). And if I pull the nozzle out a bit, it will run more. That nozzle couldn't care less about the remaining tank volume. There's sensor in that respect in the nozzle or the tank.

 

[Blade1668]

Well here is my take on it.
#1. Running fuel pump dry really bad. #2. Running out of fuel really bad.
#3. I was a "poor" kid after I got a D/L and car no $$$ for gas hardly AKA I ran out of gas many times. Now I fill up at 1/2 tank and maybe 1/4 on certain routes. "Not if west of Mississippi river"
#4. S### happens I live in hurricane and tornado belt... I keep fuel tanks full and 6-8 5 gallon cans full too.

Now just today I knew I could make it to Paducah, KY. to get gas I was still over 1/4 tank when I got there, I was getting 22-23 MPG. Now from where I'm at now I could about make it to ShadowPapa's AO on my JT but I'd fill up before I hit 1/4 just because I don't like not having a "safety margin".
Back in early 90s I was helping a car company with repos in Detroit, MI. It was a red Ford turbo coupe I think. The former owner must have carried a gas can in to work to get it to a gas station. I almost had to push it into the gas station, it coasted up to the pumps barely.

 

[ShadowsPapa]

I ran out of gas one time. I was in college, living in an apartment and was driving my Javelin to get gas. About half a block from the station the engine started to misfire - about 20 yards from the gas station entrance drive it stopped. I rolled down the driver door window, pushed the car to their drive which was all down hill to the pumps, as I got it rolling I hopped in and drove it to the pumps - coasting all the way. Talk about LUCK. Run out of gas just seconds from a gas station and be able to push the car until I could coast in. I had only myself to blame - the gauge was very accurate.

Funny thing - when I suggest to people that it's better to keep their tanks full or over the half mark in the winter they say it costs more to do that, and they can't spare the extra money. Now explain that logic to me! I've had several people insist that it costs more to keep their cars full. OK, whatever.

 

[it_trailblzr]

I drive a company vehicle that reports 50 miles til empty.
I never push it because that 50 miles drops like a rock within 20 miles.
My Jeep remains very accurate (relative to my POS Ford company vehicle) and has not let me down yet.
Company vehicle, not so much.

 

[ACAD_Cowboy]

These must be the same people who swear to god you'll get more fuel in the morning when it's cooler and thus the fuel is denser versus late in the day when it so hot and sunny... Meanwhile the tanks are below grade, typically below the frost line to limit heaveing and the fuel is always a cool 54ish.

Chuckle heads...

Once a had a dark hippie (you know the look, has all the money in the world for beer, weed, tats and tone but pan handles for groceries) chew my ear for what felt like most of the night at a bar, talking that meth head jive and fuel density and how they rip you off... that horrible feeling when you realize you don't have enough money to drink till you pass out quickly.

 

[ShadowsPapa]

These must be the same people who swear to god you'll get more fuel in the morning when it's cooler and thus the fuel is denser versus late in the day when it so hot and sunny... Meanwhile the tanks are below grade, typically below the frost line to limit heaveing and the fuel is always a cool 54ish.

Chuckle heads...

Once a had a dark hippie (you know the look, has all the money in the world for beer, weed, tats and tone but pan handles for groceries) chew my ear for what felt like most of the night at a bar, talking that meth head jive and fuel density and how they rip you off... that horrible feeling when you realize you don't have enough money to drink till you pass out quickly.

ROFLMAO. Yeah, exactly. The ground around here is supposedly a fairly steady 55 (the number I was always told around here) degrees year-round. That's the basis for ground water heat pumps.

On a really humid early spring day if I fill my 5 gallon gas cans (have to keep fuel for a generator and my lawn tractor) you can see them start to sweat as the warm humid air hits the cooler gas "cans".

I've seen this gas purchase BS on those home helper sites along with how to hold the nozzle and more - don't forget the last 4 drops still in the nozzle!

 

[PyrPatriot]

Now explain that logic to me! I've had several people insist that it costs more to keep their cars full. OK, whatever.

More gas in tank means more weight which means fewer fractions of miles per gallon. It costs them maybe $1/tank more in gas to not have their tank less than half full at all times?

 

[ACAD_Cowboy]

Ive heard the same argument as well, thats its a weight you don't need to be dragging around.

Its like drag racing, every pound you take out has a horsepower equivilebt, I used to joke it was cheaper to starve your self to look like The Machinist than to build the motor.

At 6.3lb/gallon that 30lb savings is offset by that fancy winch bumper, winch, all that trail armor, the "beadlock style" wheels with 37's and all that fucking mud you refuse to wash off because clang is cool.

 

[MPMB]

Funny thing - when I suggest to people that it's better to keep their tanks full or over the half mark in the winter they say it costs more to do that, and they can't spare the extra money. Now explain that logic to me! I've had several people insist that it costs more to keep their cars full. OK, whatever.

I remember reading some earth-first propaganda and they said 100# of excess weight in your car amounts to reducing your MPG by 1. Hmm... I don't think so, Karen.

I tempted the auto gods with my Expedition. I tested that theory. I would only fill up to 1/2 tank or so. It would get me 5-6 days of commuting. Not having a full tank also prevented me from driving the Expy around on weekends for errands and trips here and there. The only time I was able to get a decent MPG average was with ethanol-free gas at altitude on a freeway. Almost hit 16mpg in Montana with a full camping load. Commuting was 13.7-13.9. Freeway trips were 14.1.

Story time:
#1
My wife got pissed at me and has PTSD from a successful trip. January. Oregon coast. Oregon is like NJ where you don't get to pump your own gas (now they have exceptions). 2013 Ford Explorer. We go see a movie with the family, get out of the movie around midnight. Forgot to get gas before we hit the movie; I forgot I was in Oregon. Around home, most gas stations are always open.

We drove from Lincoln City to Newport with the Explorer's electronic gauge reading 12 MILES TO EMPTY.

Not one gas station was open along the way, not even a card-only place. We roll into Newport and right next to our hotel was a Shell station that was open. We passed 8 or 9 gas stations, all closed.

The entire drive the engine never stumbled. And the tank took 17 gallons, it's a 18.6 tank.

Fast forward a couple years, my wife leaves work with "30 miles to empty" notification and runs out of gas on the side of the freeway. Of course it's my fault.

#2
My sister, b-i-l, and myself drove down to Washougal, WA to watch our buddy race motorcross. My b-i-l had, at the time, a $150 '79 VW Rabbit Diesel. Flatout on I5 it did 70mph with us in it. Getting drafting help from my cousin (if I could have opened the rear hatch, I could have cleaned the bugs off his grille with tweezers), we got up to 75-76mph. It's about 215 miles to the track. Then we drive to Vancouver for dinner with our buddy, then head home. It's a 10- or 12-gallon tank. Diesel Rabbits are about 40mpg. We should be able to go round trip on a tank, no problem.

We get about an hour outside Vancouver and the engine begins to cut out. We swing right, hit the off-ramp and coast to the gas station. Crisis averted.

The gas gauge broke; it was stuck just over 1/4 tank.

Aside: One of the most fun roads to drive is the Washougal River Road. Once we got on it, my b-i-l started driving it like a road course, and I would jump from left to right, depending on the turn, for extra ballast. It was hilarious.

 

[ShadowsPapa]

More gas in tank means more weight which means fewer fractions of miles per gallon. It costs them maybe $1/tank more in gas to not have their tank less than half full at all times?

They were meaning literally it was more expensive, not related to MPG or weight. They simply believed it was costing them more to keep the tank full than to only fill when it was low. These people weren't smart enough to figure HP, mpg, weight of the truck and so on. They truly believed it hit their budget to have to keep the car full, like that extra half a tank cost more than the first half of a tank. There wasn't even logic to it!
It was before the days of being concerned about vehicle weight or MPG - this was 40 years ago.

I could understand if they were at least approaching it from an engineering standpoint.

And if a person is so concerned about the weight of the vehicle, what's all the crap in the trunk and trash in the back seat and why's it look like you live in the car?

Weight of the gasoline? Half a tank is what, 63 pounds? I lot of guys I know - including myself - could stand to lose half of that amount (25 for me) and some more........ save the seat springs and foam, save the truck springs, lose the driver.

 

[firemedic2714]

Manufacturers purposely underestimate fuel levels because running a fuel injected engine out of gas can overheat the fuel pump and injectors and cause sediment from the bottom of the tank to be sucked into the fuel filter clogging it up.

 

[Trippin01]

Pretty much a non-issue. I try to run it completely dry when I'm on dirt roads camping, then throw the Jerry can in it. I have a hard time getting it to empty out, but thats a good problem to have. My durango was Identical to this.

 

[Phishs]

I’m having a similar issue. Mine was reading 80 mile range with just under half a tank, way low. I filled it up and it went to 260 when it’s always been around 320 when it’s full. It’s also showing full, just 60 miles short on range.

 

[ShadowsPapa]

I’m having a similar issue. Mine was reading 80 mile range with just under half a tank, way low. I filled it up and it went to 260 when it’s always been around 320 when it’s full. It’s also showing full, just 60 miles short on range.

It bases miles left on recent driving history and recent mpg history. It's going to vary.
if I get 400 miles on a tank, then fill, the miles remaining on the new tank starts around 400. If I got 350 and fill, it starts lower, and how much lower depends on my last drive - if I was hauling or towing, it will drop that number down.
it's science and math, not really a mystery.
It's using historical data to some extent, perhaps even tracking the fuel used in the last few miles.

I don't sweat it, I know my my driving and my truck so only rely on it on long trips for miles remaining. I don't really care what it says I might get on a fresh tank of gas - too many variables over 300 miles - it can't be accurate anyway. It adjusts as you drive. I've seen it go up, and go down, as I drive.

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