Accuracy of the MPG gauge

[sandwich]

I have been logging everything to do with fuel consumption for my truck since day 1. Even though I take my own records, I use the MPG gauge just to see it on the fly. The first ~4000 miles this baby was dead accurate, and I mean dead-on accurate. Now it's starting to trail off.. example: my last tank was 19.8 calculated mpg, and the gauge read 19.1. The one before that was 17.8 calculated and 17.1 gauge.

Anyone have any insight? It's not a HUGE deal since I keep my own logs, just a small peeve I've been noticing.

by the way if anyone has an iPhone, get the "gas cubby" app.. it's so awesome for tracking $$$ and gas mileage

 

[chimyz]

Have you been resetting the gauge each fill up? Could that be the differential between your math and the trucks math?

 

[jpowers]

Mine is normally with in a few tenths, reporting like yours where the hand calculated is 19.4, guage reads 19.2 or somthing like that. However I did have one take where I calculated it at 23.59, and the guage read 20.8. All others are with in a few tenths.

I also use the gassy cubby it's a nice little app.

 

[M1911]

That's a lot more accurate than my 4th gen -- computer is about 2 mpg optimistic.

 

[PTY507]

Mine was readin 19.5MPG but then, i screw up with the fuel cap and had to unplug the battery to reset the lights on the dashboard. After that, it start reading 20.2 - 20.5. Usually it gave me like
~400mi per tank, and now is like ~380mi per tank.

Am not sure if this is accurate.

 

[fxoffroad]

Mine seems to be getting 18-20 city...

Personally I don't care about the gas mileage (I would of bought a Prius if I cared), gonna have to filler 'er up regardless, and its gotta be better than my former F250.

eace:

 

[Chomondely]

mpg gauge

d a few tenths high. More accurate than my LR3.
Just over 20 mpg if mostly city. A bit over 21 mpg with 80/20 highway/ city.

 

[Quentin]

3rd fillup today. Meter read 22.5mpg. Actual fill-up was 22.3mpg. So far, it has been very close. My GTI is usually 1~2mpg on the optimistic side.

I do miss all the features of my GTI's display. It did instantaneous, average mpg, range, average mph and had a feature where the A trip auto reset every time you parked the car for 2 hrs. So, like on my drive tonight to my parents', it would keep running the whole time even if I stopped for gas and reset the B trip (for tracking MPG purposes). It also doesn't make me choose between odometer, trip odometer, and mpg... it shows them all at once. VW trumps almost everyone with this driver display, though.

 

[dcon]

Mine has been surprisingly accurate. If you have the factory nav there is a feature for instant MPG displayed in graph format, it's a good feature for hypermiling...

:jk: on hypermiling.

 

[M1911]

My GTI is usually 1~2mpg on the optimistic side.

Same was true of my 2000 GTI GLX.

 

[wifesrunner]

Never thought I would see a thread on gas mileage on the T4R site! Wow, pretty impressive you take your own gas mileage records for a 4runner. It sounds like you may tend towards a hypermiler. Not that that is a bad thing, just seems like an odd vehicle choice for keeping gas mileage records.

Mine is averaging about 18.5 on my first tank according to the computer.

 

[reklov]

Mine is pretty poor in comparison. I don't drive like a mad man and I have been getting 15.5-16.2 on my TE. I thought that I would have been getting better mpgs than that.

 

[iDRiVaT4R]

According to the 4Runner computer, Ive been getting at least 16 mpg average. Thats mostly city and 10 miles hwy to and 10 miles from work. I have a scanguageII that I took from my Tacoma before I sold it, these are nice little gadgets, If you want to know accurately your mileage just get one and set it up. U can even adjust it for larger tires and what not. As of right now in the 4Runner I'm just using it to monitor Intake temp, Water temp, Voltage, and Horsepower. It was dead accurate in my Tacoma, I was getting about 13 city, 16-18 Hwy.

Check out the ScanguageII if you haven't yet, Also doubles as a code reader.
ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool

 

[mpaquette]

According to the 4Runner computer, Ive been getting at least 16 mpg average. Thats mostly city and 10 miles hwy to and 10 miles from work. I have a scanguageII that I took from my Tacoma before I sold it, these are nice little gadgets, If you want to know accurately your mileage just get one and set it up. U can even adjust it for larger tires and what not. As of right now in the 4Runner I'm just using it to monitor Intake temp, Water temp, Voltage, and Horsepower. It was dead accurate in my Tacoma, I was getting about 13 city, 16-18 Hwy.

Check out the ScanguageII if you haven't yet, Also doubles as a code reader.
ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool

Can you check the oil pressure with a scanguage?

 

[iDRiVaT4R]

^^ Oil Pressure? I don't think you can. At least I haven't seen that option yet. Another thing I wish it offered was a tranny Temp Guage, that would be awesome.

 

[wifesrunner]

I had a scangauge II when I turdocharged my S2000. It was very helpfull, because turboing a NA car can throw check engine codes until you get it tuned right and I could scan and clear all codes and fix the problem before any damage was done on my car.

It also does many things like intake and water temps and anything else that it can read through the OBD2 port (that's where it plugs in).

I don't think you can read oil pressure or oil temp with it. I know I couldn't in my S.

I might have to put it in the 4runner now that my S is gone.

 

[jgedmond]

I remembered to check my TE's mileage 10 times in the first 4000 miles, here ya go:

Fillup Computer
19.6 20.4
19.8 20.1
19.4 18.9
20.1 20.0
20.0 19.9
20.1 19.8
19.7 20.2
23.6 25.0
23.2 21.6
19.5 18.7

Although the individual comparisons show the computer to be as much as 1.4mpg high and as much as 1.6mpg low, the averages are both exactly 20.5!

In my experience, the computer does not respond accurately to changing driving conditions. For example, on a long highway trip with some city driving at the end, the computer mileage does not decrease enough to reach the fillup calculated value (the 25.0mpg computer reading). The opposite happens, when you start off with a lot of stop and go and then finish with highway driving, the computer does not increase to the fillup calculated value (last two data pairs in the list).

 

[SeattleMike]

In my experience, the computer does not respond accurately to changing driving conditions. For example, on a long highway trip with some city driving at the end, the computer mileage does not decrease enough to reach the fillup calculated value (the 25.0mpg computer reading). The opposite happens, when you start off with a lot of stop and go and then finish with highway driving, the computer does not increase to the fillup calculated value (last two data pairs in the list).

I concur, I experience that same lags.

 

[sandwich]

Have you been resetting the gauge each fill up? Could that be the differential between your math and the trucks math?

yes i forgot to mention that i do reset the gauge after each fill up.. i reset that, trip A and input all my info into the gas cubby :dancin: lol it's like a ritual i have at the pump.

Mine seems to be getting 18-20 city...

Personally I don't care about the gas mileage (I would of bought a Prius if I cared), gonna have to filler 'er up regardless, and its gotta be better than my former F250.

eace:

I'm not THAT concerned either, I just like to keep a record of what I spend on things.. not just at the pump.. I have a full budget I keep track of everything. call it an obsession but it works for me and helps me keep my savings up and spending down

Never thought I would see a thread on gas mileage on the T4R site! Wow, pretty impressive you take your own gas mileage records for a 4runner. It sounds like you may tend towards a hypermiler. Not that that is a bad thing, just seems like an odd vehicle choice for keeping gas mileage records.

Mine is averaging about 18.5 on my first tank according to the computer.

Well this is more about the gauge than the actual mileage itself lol... Not a hypermiler in the slightest.. I only average about 17.8 or mid 18's with the 4runner @ 80% highway.. if I was hypermiling I'd be getting those low 20s like some of you guys. Highest ever was 19.4 average. I keep my foot down most of the time

 

[sandwich]

I remembered to check my TE's mileage 10 times in the first 4000 miles, here ya go:

Fillup Computer
19.6 20.4
19.8 20.1
19.4 18.9
20.1 20.0
20.0 19.9
20.1 19.8
19.7 20.2
23.6 25.0
23.2 21.6
19.5 18.7

Although the individual comparisons show the computer to be as much as 1.4mpg high and as much as 1.6mpg low, the averages are both exactly 20.5!

In my experience, the computer does not respond accurately to changing driving conditions. For example, on a long highway trip with some city driving at the end, the computer mileage does not decrease enough to reach the fillup calculated value (the 25.0mpg computer reading). The opposite happens, when you start off with a lot of stop and go and then finish with highway driving, the computer does not increase to the fillup calculated value (last two data pairs in the list).

yeah see what bothers me, and what inspired this thread is that my gauge was 100% dead-on accurate the first few thousand miles. Only now is it starting to trail off. Unless it was just pure coincidence but that's kinda hard to believe.

And yeah, i do notice those lags of when you have mixed driving.. If i fill up and reset my gauge on a Friday afternoon, the MPG will be all low from city driving on the weekend...and then when monday comes and I'm doing 90% highway just going to work.. it takes the gauge all week to catch up to the 18's.