How Are Accurate Are The Fuel Gauges?

[Xenole]

Normally I fill my 1.3 Yaris up with unleaded when the last bar starts to flash.

It normally costs just ovr £29 to do so.

Yesterday, was off into Sheffield for the day (80 miles each way or thereabouts) and had half a tank left. Decided to fill up the car just in case.

Did so and it came to just under £22.........

So either petrol has doubled in price since 2-3 weeks ago, or something else.

Only 2 bars dropped for the 160+ mile trip too (so should be getting at least 640miles to a tank at that rate!)

[TheNissanMan]

I always find the bottom of the tank in whatever car I've driven goes quicker...

I guess the inidicator is set to a pre determined amount in the tank and it is possible to go above the top marker, if you go above the top setting then your going to have more in the tank than the indicator knows about so the top half would last longer...

Not the best explanation of my thoughts but think it gets what I'm trying to say accross :D

[Chuck04]

different driving conditions, mpg rates, road conditions could be a number of factors, but then also the gague only gives bars, whos to say ur not at the bottom or the top of that bar if u get me

[yarisldc]

In my 1.3 the top half of the gauge seems to last forever but then as soon as it gets to about half a tank the indicator drops all the way down to 2 bars in next to no time!

[kanarnthan]

each bar represents 5 litres i think (8 bars & a 40litre tank). Ive also noticed that once you get to 4 bars it drops a lot quicker. Maybe its just a safety thing to make sure you dont run out of petrol!!

Like the range on thr trip comp read 60miles, then i drove 10miles and it dropped to 15!! and yet i still had 2 bars left lol

[A.T.G]

When i first started to drive the lil yari it kept hovering from 3 bars to two bars... finally hit 1 bar.. I wouldn't think that accurate, and the accelleration you see if fuel "usage" is prob just a disguise to try and make sure you don't push your luck, and end up grinding to a holt on the motorway..

[Blue84]

I reset "trip A" on the odometer every time I fill up now (read about someone else doing it on here and realised it's a good idea) and I know that she does at least 300 miles to a tank, 350 at a push - so whenever she gets to around 300 miles I go and fill up. Altho that is mainly because when I go to work I do a 26 mile all round trip so I really don't wanna run out! I know that if I don't fill up at 300 then there will be usually 20 miles left before she gets really empty.

[A.T.G]

just don't let it run out....

[seveer unaek]

£36 worth of Optimax fills my beast! That's when it's empty! Emty is 300miles for me... usually fill up when it flashes at about 270miles.

So, with a 9.9 gallon tank, im getting roughly 30mpg.... Wow! That's an improvement from spring! I was getting about 27 then! Must've slowed down... i'll speed up again in a week when some fresh noises will be emitting from my engine bay!

[BlueMagic]

When I first got it, and it'd run down a little, it got to two bars, so I thought "still got another bar to go". Goes down to one bar, which immediately starts flashing. Now, I'm not very technically minded, so flashing things scare the hell out of me, and on the A1 coming into Grantham (I live in Bedfordshire), that's NOT a nice situation to be in!

I found the nearest petrol station rather sharpish and filled her up again, and now ALWAYS fill up on two bars.

I've noticed two things that do affect it though. I park forwards on my driveway which slopes forwards - it ALWAYS tells me I've got less petrol than I have when I get in the car on my driveway. The other week I got in and the last bar was flashing. "Hmmm... odd". Drove to the petrol station less than a mile away, and the sod was on three bars!!!

Also, the little resistor wassnames that you can put in post-1988 cars to give them a bit of a kick - don't. They drink petrol like you'll never believe and it can take a good month or two for fuel consumption to return to normal after you take it out.

[seveer unaek]

The last bar flashing indicates that there is one gallon of petrol left. If you estimate this to be 30 miles then you'll be ok and have no troubles worrying!

[jay dh]

the reason the 2nd half of the tank goes quicker is wen u fill up to the brim, its as if there is almost another bar on the dash cos of the overspill (or some techi term). basically u end up filling the tank and the pipes the petrol uses to get to the petrol tank. these pipes are not measured on the dash so it may be longer for the 1st bar to disapear than all the others

hope that helps

Jay

[dicey2k]

My top bar goes off after about 40 miles from a fill up, as for the others, it does tend to go down quicker after half way. I don't bother recording my miles anymore because the results are always pretty much the same. Just fill up when i have 2 bars left or when it starts flashing!

Is it not because the tank is a funny shape and appears to go down quicker after the mid point? I have known other cars do that, just a thought!

Current MPG is reading 40.0 on the nose as of this mornings drive to work! Think i'm losing my lead boot!

[Demonic Angel]

When I got my first Yaris I let it go so low the guage was telling me 0 miles left - I had to pull over and ring my boyfriend to bring me some petrol! lol

With this one a whole tank normally lasts me a month and I get about 330 miles to a tank, I normally fill up when I have about 30 miles left.

Although I've posted before about the accuracy of the digital guage, as when I got stranded, the miles remaining seemed to go down really quickly. With an analogue guage you can clearly see the amount remaining in the red bar....

Still.... I wouldnt swap my digi-guage for anything! :P

[Ismael]

Hi all,

I have been advised not to wait for the fuel tank to be "empty" to fill it up. Think it's because of the fuel pump. When you have been riding, the car usually heats up. When the tank is nearly "empty", this pump remains in air and not in fuel. It will expand when the car is hot. When you stop at a filling station to fill the tank up, the relatively cold fuel coming in may cause the fuel pump to contract. Repeated occurrences of this may cause the fuel pump to fail. It's better to fill the tank when it's half empty ...or half full :P

Hope there is some truth in the advice.

Ismael

[Ryan1985]

Must've slowed down... i'll speed up again in a week when some fresh noises will be emitting from my engine bay!

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A'PEXi Keanu?

I usually put a tenner in when I get down to 2 bars, hate filling it up, it hardly moves!

[Yaris-Nut]

£36 worth of Optimax fills my beast! That's when it's empty! Emty is 300miles for me... usually fill up when it flashes at about 270miles.

So, with a 9.9 gallon tank, im getting roughly 30mpg.... Wow! That's an improvement from spring! I was getting about 27 then! Must've slowed down... i'll speed up again in a week when some fresh noises will be emitting from my engine bay!

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Less than 30mpg!? .. omg .. you must living on the redzone all the time!

I normally get about 300 miles to a tank and 38mpg ish driving carefully. But recently i've given my motor a good workout and burned a tank a fuel going to Wales and back with 4 ppl in the car at speeds i do not condone!

And now it does over 40mpg!! 40.6 mpg to be precise and its currently on 320 miles with the gauge just starting to flash. Good result i think! Just like the good old days when the car was new and i was a granny driver!

[Fone]

My guage hardly moved until I have done about 80-90 miles, sometimes it takes 180 - 200 miles for it to drop by three bars. Every now and then, it goes UP by one bar with further driving and without filling !!!!!

So I fill her up after doing about 200 mls because I have lost confidence in the gauge accuracy.

[seveer unaek]

A'PEXi Keanu?

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Possibly....!

Less than 30mpg!? .. omg .. you must living on the redzone all the time! 

I normally get about 300 miles to a tank and 38mpg ish driving carefully. But recently i've given my motor a good workout and burned a tank a fuel going to Wales and back with 4 ppl in the car at speeds i do not condone! 

And now it does over 40mpg!! 40.6 mpg to be precise and its currently on 320 miles with the gauge just starting to flash. Good result i think! Just like the good old days when the car was new and i was a granny driver! 

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If the tank is 9.9 gallons and you get 300 miles to a full tank... you're getting less than 30mpg! The MPG gauge is waaaaay out... don't trust that thing! The Yaris tank is 45 litres, most iv filled up with is when it's been very empty and iv filled it to the brim (little spillage - d'oh!) is 42 litres. Then i had to re-fill after 300miles... that's about 30mpg i think! (maths aint a strong point!)

So, if you can get 45 litres in... then drive as normal until you're running it dead, check how many miles you've done and bingo... that's your MPG!