[i30 2020]

Hi guys,

Mine is 2014 1.8 AUTO. I don't drive much per day\week\month so it doesn't significantly hit me in the pocket.
Just more concern about theoretical issues with the fuel system in general.
I mostly drive within suburbs with 40/50 km/h limits.
Every time I refill the tank for 10L I have 6 bars on the fuel level graph and around 250KM until the next refill.
However, in around 60-65KM it drops to 3 bars and around 160KM-150KM until the next refill.
I realize this kind of information on a board panel cannot be 100% precise but can it be that inaccurate or it is a high time to see mechanics shop?

Thanks.

[mickd]

Hi, it's a ROUGH guide.
Will usually show that you can't go as far as you can, built in allowance for those that forget the fuel light is on. Yours may need a good drive to let it recalibrate.
Ours have at certain times shown- full tank 630km but 100km later has shown 620km   

[Dazzler]

Welcome,

A 1.8 Auto would certainly not be very economical particularly in a place like Sydney. I wouldn't be too concerned about your dashboard read outs. Best thing to do is brim the tank* (taking note of the odometer/mileage reading)  then run it until the light comes on. Refill at the same pump if possible to the same level as your last fill and again note the mileage.

Work out using litres purchased versus mileage covered what is your litres per 100 kilometre reading. It is probably around 10 litres or higher  it it is 12 or 15 then that might be a concern. Although it could even go that high if you only do lots of 5 or 10 kilometre drives and mostly drive in bumper to bumper traffic.

* It is not really recommended to brim a car that runs on unleaded so if this concerns you then just try and do the same thing at the same pump (fill until it clicks off say twice)

The more times you do this manual calculation the better your accuracy will get. Combining the total mileage and dividing by the total litres.

Hyundai Haven't been particularly economical cars fuel wise in the past (except for the Diesels) they have improved in recent times.

[Surferdude]

Hey Dazz.
Why is it not recommended to brim an unleaded car?

[Dazzler]

Hey Dazz.
Why is it not recommended to brim an unleaded car?

Fuel expansion and possible damage to catalytic converter I think? There is a warning in my toyota handbook I'm pretty sure. I believe diesel doesn't expand as much so less likely to cause a fue spill, but I've even read that you shouldn't brim them either.

[i30 2020]

Hi guys,

Thanks for your replies.
Forgot to mention that board panel also shows about 12,7L per 100KM consumption but 60KM-65KM on 10L is much more.

What about calculating fuel consumption this way:
1. Fill the tank until I get a pistol click.
2. Drive as I normally do.
3. In 100KM refill and see how much I fill until I get a pistol click.

Would that be a proper way?

[CraigB]

Fill tank and drive it till the last fuel bar on dash starts flashing which should leave roughly 5 ltrs then calculate the mileage after refilling.

Short stop-start drives around suburbia and city will certainly use more fuel.

[i30 2020]

Fill tank and drive it till the last fuel bar on dash starts flashing which should leave roughly 5 ltrs then calculate the mileage after refilling.

Short stop-start drives around suburbia and city will certainly use more fuel.

In my case no matter whether I drive only say 100KM or till the last fuel bar it would be only intra suburb driving with 40/50 zones.
I realize it is not the same as drive on highways but not a bumper to bumper so just wondering if it should be ~ 15L-15.5L. 

[Dazzler]

Hi guys,

Thanks for your replies.
Forgot to mention that board panel also shows about 12,7L per 100KM consumption but 60KM-65KM on 10L is much more.

What about calculating fuel consumption this way:
1. Fill the tank until I get a pistol click.
2. Drive as I normally do.
3. In 100KM refill and see how much I fill until I get a pistol click.

Would that be a proper way?

Sounds good in theory, but the general consensus to get an accurate figure is tracking the way I suggested over an extended period. There are a lot of variables which make one of/short term tests less accurate.

Just as an example cars tend to generally be more economical in warm weather as the engine gets to optimum temperature more quickly. Wet roads increase the rolling resistance of tyres which can adversely affect economy... Things like this (and others) even out over extended fuel economy tracking.

[22over7]

Hi, I feel your pain with the poor fuel economy from the 1.8 auto.

In regards to your particular usage, 50 kph needs a very light right foot to hold top gear (where the best fuel economy can be had). It's going to be very tough to get reasonable figures without any highway cruising.

To get accurate (manual calc) figures, the longer the distance covered, the better. I always fill to the second click and take the average of 3 tanks at least.

The distance to empty, the fuel gauge and the average fuel economy figures on the dash aren't very accurate. Take them as a rough guide and don't try to base calculations off those rubbery figures.

[Surferdude]

I've just set up a spreadsheet.
Been running it since 2009 over 2 cars.
Date, kilometres, litres, c/p/l, total $, and a progressive Litres/100klms.
I also have a total Klms column and a Litres/100 Kim's since last fill column (which is by necessity,  not overly  accurate.

[Surferdude]

All of which tells me my 6 speed Corolla is better than my 5 speed FD by about 1.5 litres per 100 Kim's.