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Miles to Empty

66K views 88 replies 47 participants last post by  spta97 
#1 ·
Questions.

Noticing what I think it poor fuel economy via the gas gauge.

Quick Background.

Picked up my new-to-me 05 about 2 weeks ago. Filed it up with 87oct and got about 300 miles mostly city driving - reported via the odometer -. Took the truck all the way down until the empty light came on. The gas gauge was below the "E" line.

Friday morning filled it up with 92oct and exactly 21.2 gallons. ( As of Today) -Drove a total of 57miles , reporting on the odometer, and the gas gauge shows I have plowed through a quarter of a tank. Using the trip features on my Nav the trip feature estimates about 272 miles to empty.

Tank size of my 05 is 28 gallons.
( city driving 12 mile per gal x 28 = 336 total miles )
( 28 gal capacity / 4 = 7 gallons per quarter - roughly )
( 12 miles per gal * 7 gal/quarter = 84 miles per quarter tank )

quick math shows I should get "around" 84 miles per quarter tank.

84 "Should get" miles vs. 57 on the odometer.

So.. My observations are as follows. My gauge is not accurate, the Nav trip meter is close. Going to have to watch the odometer.

Could it just be an inaccurate gas gauge?

Anyone else have this type of problem before??


P.S. - To combat this problem, did a fresh oil change and switched over to syn oil - new air filter etc. Will top off the tank tonight and start monitoring the mileage again.
Tires are Cooper Discoverer ATR - All brand new, running about 36psi per tire according to the sensors.


Thanks
~Tim
 
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#3 ·
There has been a ongoing problem with the fuel sending units. There is a TSB to replace the sending unit to correct this problem but most seem to keep having the same problem again.
 
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#4 ·
I've noticed that, no matter what kind of mileage you've been getting, the "Distance to Empty" is always the same (378 miles on mine) with a full tank. This tells me that the computer isn't using current average consumption to calculate, only multiplying the reading of the gas gauge by a constant (378 divided by 28 is exactly 13.5, a bit too coincidental for my liking). I've noticed this when I'm towing my trailer, and the mileage is ~10mpg, versus getting 15 mpg, the DTE is still the same.

I don't rely on the DTE. When I'm towing the trailer, I start looking for gas when the trip odo is more than 200. Without the trailer, I start at about 280.

Keith
 
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#6 ·
Ok so I ran my tank down until the gas light came on. Check my miles to empty and it said 38. Drove around for a while check it again and it was 0 or all stars. The neddle was on the E line. Got to the Pump but was only able to put 24.5 gallons in. Is the computer wrong or does is just not count the 3 gallons as a reserve?
 
#7 ·
The computer keeps several gallons in reserve when running the Distance to Empty.
 
#8 ·
Yep, my experience as well. You can run it down to the stars and it'll only hold about 24 - kinda defeats the point of having a 28 gallon tank if it's going to lie to you about how much you have left.

One thing I have found though is that the OBD-II data does not lie. I have a bluetooth OBD scanner connected to my tablet and just go by the percentage of fuel it says is left. When the stars come out, it says there is 15% left in the tank... I'll run it down to about 5% before I chicken out and get gas.
 
#9 ·
It is not really considered it is telling you a lie. It is more of a saftey feature. Some people like to push their chances a lot. So, that reserve is for those kinds of people. Also, any good driver knows it is not best to always run a car until it is at say 5%, as in your case. So, when Nissan designed the car to the point where the miles to empty turn to ---, that is enough warning for any driver to please fill up.

For most cars, when your miles to empty turns to stars or dotted lines, you do have atleast 30 more miles to drive further. But why push your car so far before you gas up? It truly hurts the car if you keep on driving until 55 or until you are truly about to make the car stall. Not the best to do on any car.

So, basically, try to gas up before your miles to empty turns to dotted lines. It is better for the engine. But the car is yours, so you can do what makes you feel comfy. I hardly ever let my cars go below half tank. That is just me. The only time it goes below half tank is when I am traveling. And which, I do gas up at restroom breaks or as soon as I make it to my destination.
 
#10 ·
1/4 Tank is when I usually fill up, depends on needs at the time. How accurate is the Bose display for calculating correct mileage per gallons used.
 
#12 ·
I haven't really calculated how good the computer's MPG is.. I will tell you this. When I filled up it said 250 miles to empty....drove about 34-36 miles and checked it again and said 234 to empty. So i guess it tried to calculate on your driving habits which can vary if your driving alone or with the wife and kids.

I'm only asking because I can foresee the future on a road trip when the wife sees only 8 miles to empty and panic sets in, telling me WE HAVE TO STOP AND GET GAS NOW!!!!!!

Just a FYI.... I took the truck on my favorite straight away where I do my speed testing and Got her up to 106 m.p.h. before I had to slow down. Same straight away with my QX4 only got to 93 m.p.h.
 
#14 ·
The New QX models are growing on me, love the vent side. But at the price All I can do is look and Admire them as I go on down the road.
Yea I ran the the 2010 very quickly up over 100 mph when I test drove it before we signed on the Dotted line. Felt very stable and had plenty more, assuming the computer shuts down the top speed some where??? My wife was like Heck ya I like it.. Its fast for a 7000lb suv.

I don't leave the Fuel status on display, only use it for reference and to help my driving habits, I can consistently see 18.6 to 19mpg if I do a reset and drive 15 miles or more driving miss daisy on country roads and hi ways, guess I need to do the manual math and see how accurate the mpg display is. Reason I'm asking is I can really keep my foot in the gas in city or on country roads playing around have seen as low as 8.6 mpg from reset and driving around for miles have watched the gas hand drop it seemed like, Like I have said since owning the Armada, its a sleeper and has the mindset of a dragster when its needed. Love this Suv.
 
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#18 ·
How accurate do you believe the "Miles to Empty" estimate is? I let it get down to 34 before stopping, about 14 miles from a preferred gas station. Also, the low fuel warning light or tone never came on, at what point does that occur?

Thanks
 
#19 ·
I've got the same truck and I've seen the low fuel warning go off on the dash around 25-30 miles to empty. The fuel gauge was slightly above E. The manual says there is some reserve fuel at E. I have yet to be at or below E to see how long it can run on fumes. Hope I don't have to find out.

"Miles to Empty" seems fairly accurate/useful to me. The Armada knows how much fuel is in the tank and -probably- figures it out with your average MPG. Helpful enough on long trips to estimate when I have to stop.
 
#21 ·
I can comfortably go 60 miles (highway city mix) after the low fuel light goes off and then put in about 25 gallons. So approx 3 gallons left @ 14mpg = another 42 or so to empty. I don't do this often, it's not good for the fuel pump.
 
#22 ·
In my experience, the MPG readout is very accurate, but miles to empty is overparanoid about running out of fuel.

Using the OBDII fuel level, you get a much more accurate picture of what you have left. I go until OBDII says I have 5% fuel remaining, which is quite a while after the low fuel warnings start bugging me.
 
#23 ·
I never drive it until empty, I get too paranoid. Anytime its between half and quarter tank I refill. Thats just me though. My wife drives her car until the light flashes alot of times.
 
#24 ·
I noticed something kinda off over the past couple of fill ups and wondered if anyone who has the 17 Armada noticed it too. The documented gas tank size is 26 gallons, dealer confirmed this.
Today, the gas needle was in the red and showed I has roughly 63 miles till empty so probably 3-4 gallons. I filled up the tank and it only took 18 gallons and it was completely full. There is no way there was still 8 gallons in the tank. My guess is the tank is not actually 26 gallons. Anyone else notice this? Going to be doing some traveling and it got me thinking.
 
#25 ·
My 2015 is stated as having a 28 gallon tank, but the most of I've ever put in when hitting empty is 26 gallons. Most of the time when the range tells me I've got less than 30 miles, I can only get 24.5-25 gallons before full. So I think the tank is giving you a generous reserve amount where you could still drive 60+ miles after hitting empty.
 
#74 · (Edited)
When my fuel sending unit failed to 1/4th full and my wife ran out of gas, my 2005 took 28 gallons on the nose.

My understanding is the new Armada has a 26 gallon tank.
 
#26 ·
I thought about the reserve but whats interesting, is that if you read up on the QX80, there are numerous problems with not being able to register that last 7 gallons of gas in the tank.
Sounds like a known problem that carried right over to the Armada. Something about the sensor mounted too high on the tank.
 
#29 ·
Interesting topic.

One thing I had noticed when shopping and researching specs prior to purchasing my 17, Armada and depending on the source, I have seen several specs call out the tank size as 28 gal while others are calling 26 gal.

The Main Nissan site and the brochure show 26 gal, multiple Nissan dealer websites show the 28gal, I also did multiple model spec comparisons using, KBB, and NADA, where one called it 28 gal, the other showed it as 26 gal.

I asked one of the dealers which was accurate. They were not 100% either way but speculated 26 gal was likely correct.


I have a therory on why your warning lights are coming on earlier then we are typically expected.
All 4 200 series Toyota Land Cruisers / LX570, all show what we think of as distance to empty here in the US , when I think what it is actually saying is cruising range not DTE the 200 series give you a 5 gallon reserve .
A lot of these vehicles like the Land Cruisers and Patrols are sold, having that 5 gallon reserve could be very critical info, and I think it seems to be a common setup for global market vehicles like this.
Thinking that in many of these countries they might not have a gas station on every corner or every 20 to 40 miles apart on the interstates. So setting these global rigs up with a healthy fuel reserve like 5 gal,
 
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#30 ·
Could it also be that the fuel is used to cool the pump? Showing it empty before it actually is may be a safeguard. The pump (fuel sending unit) is inside the tank right?. Running it completely empty leaves the pump "unexposed" to fuel that would otherwise cool it. I can't say for certain, just a thought FWIW.
 
#31 ·
I checked the spec for the QX80, also Patrol based and it matched up with the 26Gal. Spec that some sites showed for the 17 Armada. I am thinking the 26 Gal spec is likely the correct size, the 28Gal is likely just carried over spec data from the old Titian based Armada.

I really don't think its a malfunction. It might be to protect the pumps.
After owning 3 Land Cruisers and 1 LX570, all exhibiting programing for 5 gallon reserves, all those Toyota rigs were global platform vehicles very similar to Nissans global marketed Patrol, which the Patrol is the new Armada, I am really inclined to believe its likely just a similar situation with the Armada/Patrol, that its simply programed with a that hefty 5-6 gal reserve.
 
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#32 ·
This is surprising, I checked the Nissan Patrol spec sheet on Nissan Australia - and it says 140 liters, which comes out to just over 36 gallons...

Quite a difference for a vehicle that should be pretty much exactly the same. I hope the badging isn't too hard to buy... I think it looks nicer with the Patrol badging and the color matched rear view mirrors... Too bad we can't opt out of the chromed out version that's available in the US.

http://www.nissan.com.au/~/media/Fi...cations/2015-08/Y62-Patrol-Specification.ashx

http://www.nissan.com.au/Cars-Vehicles/Patrol/Range-and-Pricing

They got some cool Patrols there:

http://www.nissan.com.au/Cars-Vehicles/Patrol-Cab-Chassis/Overview

http://www.nissan.com.au/Cars-Vehicles/Patrol-Y61/Overview
 
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