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Author Topic: Last 1/4 in tank seems to go fast. Back to Topics
Terzo

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Orange County

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Message Posted: Mar 22, 2012 4:07:06 PM

Anybody else notice that the last 1/4 in their gas tank seems to burn up faster than at any other level? When I first bought my truck it seemed to be more consistent, but now I have to keep the tank at a higher level or I'll burn fuel too fast. You'd think with less weight to carry around that I'd be getting better gas mileage, but I'm experiencing just the opposite. Anybody got any ideas what's going on?
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sagnat
Champion Author Riverside

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Message Posted: Jan 7, 2013 1:05:19 PM

Probably because the fuel gauges aren't linear but rather a best guess on how uch is remaining.
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hornet17
Champion Author Vancouver

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Message Posted: Jan 7, 2013 10:04:33 AM

inaccurate fuel gauge? Most of them are.
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musicreporter
All-Star Author San Antonio

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Message Posted: Jan 7, 2013 9:53:57 AM

yes
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wlotocky
All-Star Author Florida

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Message Posted: Jun 15, 2012 1:04:50 AM

yup
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Seamus4513
Champion Author Orange County

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Message Posted: Jun 14, 2012 4:00:22 PM

I havent noticed. In my old ES, my avail fuel increased in hard right turns
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minet
Sophomore Author British Columbia

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Message Posted: Jun 11, 2012 9:16:51 PM

yeah the lower the level of fuel, the faster it burn out. i always fill up when its 1/2 tank. i get more milleage everytime.
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nordlead
Veteran Author Syracuse

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Message Posted: Jun 11, 2012 1:09:56 PM

when near empty, I can gain 1/8th of a tank just by driving up a hill :-D

Until (as mentioned below) there is a system to measure input and output of the gas tank no gauge will be very close to correct. I just watch my trip meter and reset it at every fill-up.
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Jude23
Rookie Author Vancouver

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Message Posted: Jun 10, 2012 10:12:49 PM

Yes! Drives me crazy too. I always gas up in the states and if I've not watched my amount of driving and am coming close to that 1/4 tank mark it's scary how fast it can plummet while I'm doing 110kph heading for the border! :)
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prob52
Rookie Author California

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Message Posted: Jun 9, 2012 7:54:44 PM

My gas light comes on when I have 50 miles left. I usually put gas in when the light comes on.
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diesdown
Champion Author North Carolina

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Message Posted: Jun 9, 2012 6:03:36 PM

That's because it most likely is NOT a full 1/4 tank......instrument measurements vary greatly.
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vikings80
All-Star Author South Dakota

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Message Posted: Jun 8, 2012 9:15:55 AM

quick
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kxy4fw
Champion Author Denver

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Message Posted: Apr 27, 2012 9:23:21 AM

reallllll fast!
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dontuknowOH
Champion Author Ohio

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Message Posted: Apr 26, 2012 12:53:01 PM

The shape and angle of the fuel tank is different on some vehicles,plus where it is placed for safety sometimes determins the capacity at different fuel levels.

Others have mentioned linear reading at the guage indicator may be designed a bit crude,that's often the case,same for sample readings by the ecu on more modern vehicles.

It's not good to always rely on the low fuel light before adding fuel myop.The other reason may be you just watch the guage more when running close to empty,concerned about the nearest location for refueling.Gas cans are no longer a cheap ticket item,but having one on board,well.....they are hard to borrow from strangers! LOL
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JCLNC
All-Star Author Greensboro

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Message Posted: Apr 23, 2012 3:57:40 AM

I try not to let my tank go below a 1/4.
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cheapmonkee
Champion Author Portland

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Message Posted: Apr 23, 2012 1:23:43 AM

I keep mine fairly full. The largest fill this year was 7.75 gallons. My tank is a little more than 12 gallons.
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Z12
Champion Author Toledo

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Message Posted: Apr 22, 2012 8:50:37 PM

Yes, it does
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Titanic1985
Champion Author South Carolina

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Message Posted: Apr 22, 2012 6:50:19 PM

Hello Terzo. I've read the posts on this thread and the conclusion of non-linear gas guages is correct. That said, there is another factor involved. Last year, I read an automotive article regarding gas guages and it is a no win situation for the manufactures. If a gas guage goes off full after just a few miles of driving, the driver feels the vehicle is getting poor gas mileage. If, on the other hand, the guage stays on full longer, that same individual thinks the vehicle gets great gas mileage. Since the guages are based on a float system in the tank connected to a variable resistor to the guage, the manufactures tend to keep the guage at full longer followed by a more rapid plunge to empty. It is, in reality, a marketing ploy and was well documented in this article using the same drivers and the same vehicles. I never thought of this issue until I read the article.
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Tweak3D
Rookie Author Tacoma

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Message Posted: Apr 20, 2012 9:42:27 AM

A linear fuel gauge would be nice, but isn't so easy to design and maintian between multiple lines of vehciles. This is because of the shape of the fuel tank changes making each fuel take require a unique calculation. Newer cars are better because they use a combination of the feed back from the fuel tank sensor along with fuel flow #'s from the injectors and can give us a fairly accurate idea of how we are doing.
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JimBlake56
Veteran Author Akron

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Message Posted: Apr 12, 2012 11:54:56 AM

Non-linear fuel gauge is pretty common.

Sometimes the divisions on the gauge are skewed to reflect that, for example the space between empty & 1/4 is big, then the space between 1/4 & 1/2 is smaller, etc. Sometimes 3/4 is very close to the top.

On some cars the gauge actually works that way, but the stylists have decided that it looks better if the gauge divisions are evenly spaced.
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mnrick041
Champion Author Twin Cities

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Message Posted: Apr 10, 2012 1:13:27 AM

I had a car once that seemed to stay at full for a long time, then it would drop, stay at about 3/4 for awhile and then it would drop like a rock. My car I have now shows me "miles to E" on a dash readout, that is a little more informative than the old gas gauges were.
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13Octane
Champion Author Tucson

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Message Posted: Apr 2, 2012 11:50:34 AM

nope
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RacerGene
Champion Author Alabama

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Message Posted: Apr 2, 2012 9:56:49 AM

just the meter that's not accurate
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forresj
Champion Author Wilmington

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Message Posted: Apr 2, 2012 9:10:01 AM

no i never let the tank drop below 1/4.
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MertieMan
Champion Author Lexington

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Message Posted: Apr 2, 2012 7:44:46 AM

You shouldn't let your tank get this low.
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WEDDY
Champion Author Phoenix

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Message Posted: Apr 1, 2012 8:03:32 PM

Yes.
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Jescareno22
Veteran Author Toms River

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Message Posted: Apr 1, 2012 7:32:19 PM

no
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KansasGunman
Champion Author Kansas

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Message Posted: Apr 1, 2012 6:09:43 PM

Wouldn't know...can't remember the lat time we let the tank get below half on any of our vehicles.
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jamieg2012
Veteran Author Sioux Falls

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Message Posted: Apr 1, 2012 1:43:34 PM

part of it is how much gas gets on the sensor for how full

as it moves you will go back and forth from reading empty to about half

that is what my car usually does and it is based of pressure caused by more fuel so the road grade changes to give you a hill that goes up some and it makes gravity pull all the gas back to the sensor and you read more than is there - only a level parking spot will give you the right reading since even driving changes how much pressure on the sensor since stopping and the gas will still keep going forward until it hits the front of the tank then settle back down
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pacecar68
Champion Author Oakland

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Message Posted: Apr 1, 2012 12:53:25 PM

you are gambling by letting your tank get below 1/4 a tank. the fuel is a coolant for the fuel pump. burn the pump up and you will be surprised at how expensive to replace.
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DCD_Guy
Rookie Author San Francisco

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Message Posted: Mar 27, 2012 3:05:45 AM

It's the fuel gauge designed like that, non-linear to emphasize the most
concerned area. Try a digital fuel meter, you will get linear readout.
The engine will not burn faster like you said. Let me know if you need
help to do the test with a good linear meter.
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sluggopyle
Champion Author North Carolina

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Message Posted: Mar 25, 2012 12:51:44 AM

=> You get the best gas mileage on a full tank and the last quarter tank does have a lower MPG than the 1st quarter mile if you went by your meter. <=

No. You don't. You're looking at a non-linear gauge; the "1/4" mark is not really 1/4; it's less. If the marks showed accurately how much gas was in there, they would not be evenly spaced. Conditions being equal, you get the same mileage with the first quarter as you do with the last-- it's just not telling you accurately where either one is.
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Pucelle
Rookie Author Rochester

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Message Posted: Mar 24, 2012 7:30:26 PM

You get the best gas mileage on a full tank and the last quarter tank does have a lower MPG than the 1st quarter mile if you went by your meter.

But if you go on a long trip on the highway using a full tank you will see that you get the same MPG through out the trip so it's just the meter that's not accurate.
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greydog13
All-Star Author Iowa

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Message Posted: Mar 24, 2012 7:09:13 PM

I don't generally let the tank get much below 1/2. I fill up more often but it does not hurt as much $$ when I do---
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kxy4fw
Champion Author Denver

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Message Posted: Mar 24, 2012 9:57:30 AM

Yup.
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OceanArcher
Champion Author Mississippi

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Message Posted: Mar 24, 2012 9:02:40 AM

Most gas tank metering systems are non-linear. They try to make it such that the gauge movement matches the shape of the tank, but darned few ever manage it. Until we get an integrated system that both measures how much fuel is pumped into the tank, and compares it with the fuel usage, then we will just have to accept there is a level of error in the gauge
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gobux10
Champion Author Ohio

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Message Posted: Mar 23, 2012 9:07:25 PM

Appears 2
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13Octane
Champion Author Tucson

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Message Posted: Mar 23, 2012 6:34:30 PM

really?
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jes
Champion Author Pennsylvania

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Message Posted: Mar 23, 2012 5:06:40 PM

Every vehicle I've owned has been like this. I just come to expect it.
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Dennis783
Champion Author Des Moines

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Message Posted: Mar 23, 2012 9:27:55 AM

I have noticed that on the fuel gauge. I ignore that and look at the fuel range display
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gasmask78
Champion Author Virginia

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Message Posted: Mar 23, 2012 12:53:03 AM

It's because most older cars have little weights in gas tanks.
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gougedQC
Champion Author Montreal

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Message Posted: Mar 22, 2012 7:30:30 PM

I've noticed this as well.. non linear measurement.. I think its a deliberate ploy by the car companies..all of them..

They know most people dont run to empty...but rather to perhaps a little under half..so they skew the readings to make you thing your going farther on your tank of gas..
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rick_evans
Champion Author Boston

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Message Posted: Mar 22, 2012 7:00:12 PM

Have you noticed that the first 1/4 tank takes much longer? Every car I've ever owned including my current 07 Corolla has had a non-linear reading fuel gauge which stays pegged at full for the first 50 to 80 miles while appearing to go fasted through the last 1/4 tank.
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