Recent Topics
TGMO 0W-20, 10,300 mi, 282,000 on 2012 Elantra
by schuylkill. 10/19/18 05:14 AM
Lowest W grade oil
by OilUzer. 10/19/18 04:50 AM
ST Conventional SN Plus
by motorguy222. 10/19/18 02:42 AM
schaefferoil or Amsoil
by s2krunner. 10/19/18 02:29 AM
Pennzoil conventional oil meets api sn plus
by chris_84. 10/18/18 11:45 PM
TGMO in new Honda turbos?
by BTLew81. 10/18/18 11:26 PM
'02 Explorer Sport Trac: 302k mile update
by 14Accent. 10/18/18 10:43 PM
BMW 335 Quick Coolant Change
by antonmnster. 10/18/18 09:58 PM
190k miles
by Marco620. 10/18/18 09:56 PM
tire rotation/jack location
by mobilaltima. 10/18/18 09:23 PM
Apparently I'm not allowed to...
by BMWTurboDzl. 10/18/18 08:41 PM
2014 Cruze 2.0, AMSOIL DHD 7k miles 68k total
by Rat407. 10/18/18 08:32 PM
Stabilizer needed for 5-6 month storage?
by Quattro Pete. 10/18/18 08:29 PM
Clearance ST filter cut open
by barkingspider. 10/18/18 07:56 PM
0W20 Required for Jeep Auto Stop/Start
by harbor. 10/18/18 05:42 PM
Newest Members
Whyssosseriouss, TNflash, The74impala, Ryan1122, ston123
66244 Registered Users
Who's Online Now
39 registered members (dnewton3, Bailes1992, dalton, Char Baby, berniedd, 5 invisible), 686 guests, and 36 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics292,166
Posts4,875,206
Members66,244
Most Online2,494
Oct 17th, 2018
Donate to BITOG
Previous Thread
Next Thread
Print Thread
Hop To
Fuel Level Gauge Accuracy #4591338
12/01/17 07:16 PM
12/01/17 07:16 PM
Joined: Sep 2015
Posts: 873
California
mbacfp Offline OP
mbacfp  Offline OP
Joined: Sep 2015
Posts: 873
California
Have a F550 with the 28 gallon front tank and the 40 gallon rear tank. The rear tank was showing 1/4 left and when I refueled it only took 22.5 gallons or so to fill up. Is that normal to be off by so much? Thanks and hope everyone is well.

Last edited by mbacfp; 12/01/17 07:16 PM.

2014 F-550 PSD..........M1 Delvac ESP 5w-40 + OEM
2018 Dodge Charger SRT Hellcat
2012 Toyota Sienna LTD 3.5L V6
2003 Dodge Durango R/T 4x4 5.9L V8
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591349
12/01/17 07:27 PM
12/01/17 07:27 PM
Joined: Jun 2013
Posts: 1,059
iowa
Traction Offline
Traction  Offline
Joined: Jun 2013
Posts: 1,059
iowa
They have always messed with fuel level gauges. It was a big problem at one time when the level gauge was probably accurate, and people got upset when the gauge started dropping from the full mark not long after filling up. So, they made them stay on full for a long time, then it would drop like a rock after 3/4. I still think it's that way now.

Last edited by Traction; 12/01/17 07:28 PM.

Certified Tire Service Instructor since 2009
50 Chevy Fire Truck
13 Tahoe Pursuit
97 C5 Corvette
00 BMW M Roadster
02 Camry
12 Camry
81 Camaro
55 Chevy C4
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591350
12/01/17 07:29 PM
12/01/17 07:29 PM
Joined: Apr 2008
Posts: 12,911
Onondaga County
Miller88 Online content
Miller88  Online Content
Joined: Apr 2008
Posts: 12,911
Onondaga County
I don't think I've ever had a Ford with an accurate fuel gauge ...


18 Forester 2.5I 6M
00 Jeep Cherokee
01 Ford F-350 XL 4x4 5M
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591360
12/01/17 07:34 PM
12/01/17 07:34 PM
Joined: Sep 2015
Posts: 873
California
mbacfp Offline OP
mbacfp  Offline OP
Joined: Sep 2015
Posts: 873
California
Thanks guys. Always thought it was off when refueling and started to take more notice. As always, appreciate the input.


2014 F-550 PSD..........M1 Delvac ESP 5w-40 + OEM
2018 Dodge Charger SRT Hellcat
2012 Toyota Sienna LTD 3.5L V6
2003 Dodge Durango R/T 4x4 5.9L V8
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591363
12/01/17 07:39 PM
12/01/17 07:39 PM
Joined: Oct 2015
Posts: 441
MN
TmanP Offline
TmanP  Offline
Joined: Oct 2015
Posts: 441
MN
There's what's called a "full reserve" so it stays on F for a while (maybe a couple of gallons). The same is true for "E" - when it indicates empty, you have a little gas left. This is pretty common. The automakers want to have their cake and eat it too: they want to give the illusion of good gas mileage (first half often takes longer to burn because it's sometimes much more than a half) but they want to make it so customers don't run out either. Trucks usually have more reserve because possibility of abysmal mileage (towing, idling, etc).

I noticed you have a Sienna. So do we. Notice how its gas gauge works? It has about six or seven positions that it's always in, it doesn't act even remotely linear. 21 gallon tank, 3 gallons on F, about 4 gallons left when on E, stays close to F for a while, then slowly moves down. From 3/4 to 1/2 is pretty quick, then it gets stuck at the 3/8 mark for seemingly forever. After that, it rockets toward "E", and I've checked that there's at least three gallons when the gauge indicates completely empty. I drove on the light for 25 miles, then put in only 17.7 gallons or so. This means you can drive 100 miles on the light on the highway!


2012 Toyota Camry 2.5 30,000 mi
2015 Chevy Silverado LT Z71 5.3 V8 30,000 mi
2010 Toyota Sienna 3.5 V6 150,000 mi
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591380
12/01/17 07:57 PM
12/01/17 07:57 PM
Joined: Nov 2009
Posts: 4,977
Houston, Texas
motor_oil_madman Offline
motor_oil_madman  Offline
Joined: Nov 2009
Posts: 4,977
Houston, Texas
I always thought it was because the fuel drowned the float when it was full, so you had to burn a few more gallons before it went down.


2007.5 dodge cummins 6.7 liter. Chevron Delo400 15w40. 7000 mile or 250-300hr intervals.

Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591382
12/01/17 07:57 PM
12/01/17 07:57 PM
Joined: Sep 2015
Posts: 873
California
mbacfp Offline OP
mbacfp  Offline OP
Joined: Sep 2015
Posts: 873
California
Yes, I have noticed that as well. My Mazda also stays full for a while then falls all of a sudden. Great info. Thanks.


2014 F-550 PSD..........M1 Delvac ESP 5w-40 + OEM
2018 Dodge Charger SRT Hellcat
2012 Toyota Sienna LTD 3.5L V6
2003 Dodge Durango R/T 4x4 5.9L V8
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591479
12/01/17 09:49 PM
12/01/17 09:49 PM
Joined: Mar 2017
Posts: 126
northwest pa
justintendo Offline
justintendo  Offline
Joined: Mar 2017
Posts: 126
northwest pa
sounds like a pretty accurate ford gauge to me. every ford i have had, going back to a 1986 model...always has a few gallons once you hit "E". kind of like a reserve, i always thought they did it so people didnt run out of gas.


2013 escape 2.0 awd mobil 1 10w30ep
2008 fusion 2.3 mtx redline 0w20
1996 f150 4.9 2wd mtx mobil 1 10w30hm
1999 kaw zrx 1100 redline 10w40
many husqvarnas
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591696
12/02/17 07:19 AM
12/02/17 07:19 AM
Joined: Jan 2010
Posts: 111
Panama CIty, Florida
mahansm Offline
mahansm  Offline
Joined: Jan 2010
Posts: 111
Panama CIty, Florida
With the float on a lever arm with the pivot at the top of the tank and a linear potentiometer
driving the gauge, you get no movement until the float drops from the top of the tank
where it was pinned by the high fuel level. You then get slow movement which increases
in speed as the fuel level drops. Depending on the length of the arm, you'll reach empty
with some fuel left in the tank.

I had a Pinto once that had the gauge above full when the tank was full. Took about 1/4 tank to drop
to F, another half tank to drop to an indicated 1/2, and it was rapid from there down.

In comparison, all the Mercedes I've owned had fuel gauges with the marks spaced unevenly on
the gauge but dead accurate regarding the remaining fuel level. The gauge moved away from full
almost immediately after leaving the station.

My current Honda Odyssey gauge is fairly accurate but the low fuel light comes on with 5 gallons
remaining (out of 21). There's still 3 gallons in the tank when the needle gets to "E".

Last time I fueled my motorhome the gauge was midway between 1/4 and 1/2 and it took 160 gallons of
#2 Diesel (260 gallon tank).


'14 Honda CR-V (toad)
'09 Honda Odyssey
'99 Bluebird Wanderlodge 43 LXi
Re: Fuel Level Gauge Accuracy [Re: TmanP] #4591733
12/02/17 08:12 AM
12/02/17 08:12 AM
Joined: Apr 2014
Posts: 1,273
South Central PA
Delta Offline
Delta  Offline
Joined: Apr 2014
Posts: 1,273
South Central PA
Originally Posted By: TmanP
There's what's called a "full reserve" so it stays on F for a while (maybe a couple of gallons). The same is true for "E" - when it indicates empty, you have a little gas left. This is pretty common. The automakers want to have their cake and eat it too: they want to give the illusion of good gas mileage (first half often takes longer to burn because it's sometimes much more than a half) but they want to make it so customers don't run out either. Trucks usually have more reserve because possibility of abysmal mileage (towing, idling, etc).


Wish the S10 was this way. If you let it get to E, you're in big trouble. That was a fun day...

We had a 1998 Ford Ranger 3.0 V6 at work a while back. The fuel gauge would drop from F in a hurry. Had a 17 gallon tank, but when the check gauge light (aka look at the fuel you idiot, lol) came on the MOST you could put in was 13 gallons. Not fun driving long distances, and I never wanted to risk it.


'17 VW GTI 2.0T - 6MT - 9K - Edge 0w40
'15 Camry SE - 2.5 - 20K - PP 0w20
'99 S10 - 2.2 5MT - 156K - PP 10w30
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4591743
12/02/17 08:20 AM
12/02/17 08:20 AM
Joined: Jun 2003
Posts: 5,926
Illinois
SHOZ Offline
SHOZ  Offline
Joined: Jun 2003
Posts: 5,926
Illinois
Both my Hyundais are fairly accurate. When the low fuel light comes on there's about a gallon and a half left. On the Gen coupe when the light comes on it's usually around 50 miles to empty displayed, but when the light comes on the display blanks out. Turbo gets limited to 5 psi when the low fuel light is on too.

Accent gets about a 100 miles to the mark and 475 miles to the full tank. I usually figure 75 miles when the light comes on. The Gen Coupe I figure about 45 miles when the light comes on.

haven't ran out of gas yet.....


2008 Hyundai Accent 1.6L 5 sp manual hatchback
2010 Hyundai Genesis Coupe Track 2L Turbo 6sp manual
Re: Fuel Level Gauge Accuracy [Re: SHOZ] #4592432
12/02/17 09:38 PM
12/02/17 09:38 PM
Joined: Mar 2015
Posts: 5,097
Virginia
bbhero Offline
bbhero  Offline
Joined: Mar 2015
Posts: 5,097
Virginia
My car lies to me all the time. It always has more in it than what the gauge shows. Hard to know how much to put in that doggone car. It's off by at least 2 gallons on average.

Last edited by bbhero; 12/02/17 09:39 PM.

Nissan Altima 3.5 Coupe
Quaker State High Mileage 5w30 Purolator Boss 14610
"Treat your family like your friends and treat your friends like your family."
Re: Fuel Level Gauge Accuracy [Re: mbacfp] #4592493
12/02/17 10:37 PM
12/02/17 10:37 PM
Joined: Sep 2004
Posts: 7,604
Marshfield , MA
andyd Offline
andyd  Offline
Joined: Sep 2004
Posts: 7,604
Marshfield , MA
Accurate or not, you disobey it at your peril. My '58 VW bug had no gauge, just a 1.1 gallon "reserve tank". It was just a lower pickup with a shut off. The sinking feeling of the engine dying, followed by the relief of the engine restarting was enough to fully impress upon you of the need for gas. grin2


'16 Camry LE STP synth 0w20 and STP filter. the Fridge

1994 Ranger ,the Rat, 5w30 dino, STP filter

'16 Camry SE, Valvoline HM 0w20 and OEM filter
Thick oil is better grin2

BOB IS THE OIL GUY® Powered by UBB.threads™