Corolla Fuel Guage - overly conservative?

[zx81]

Had my 22 Corolla 1.8 for a few months now and have noticed that the fuel guage seems to be ultra-conservative to the point of me wondering if there is actually an issue with it, or if this is a known Toyota thing. 

Example this week - the fuel guage is showing a line or two above the "R" mark.  The estimated capacity left is saying about 40 miles.  So, I fill up expecting to be quite low.  I only manage to fit 31.5 litres in.  So in a 43l capacity tank, that means i must have still had 11.5 litres in there - thats practically 1/4 of a tank! 

I hve been getting roughly 60 mpg with this car, and this bears out with the trip odometer.  I was on 410 miles when i refilled 31.5 litres (6.9 gallons) so that works out at 59 mpg).  So if i had 11.5 litres left i.e. 2.5 gallons, surely i could have expected to go another 120 miles before a refuel?  Why would the fueld guage look so low, and be saying you've only got 40 miles left?

Anyone else noticed this? Would be interested to know whether people use the fuel gauge to decide when to fill up or if they just base it on their trip mileage and known mpg? For example, if i'm solidly getting 60mpg (which to be fair to the trip computer does seem to be accurate), and I know i fill up the tank full each time (9.5 gallons) then surely I should expect a good 540 miles per tank, rather than dashing off to the garage at 400 which is what it seems to want me to do?!

[dee123456]

Sounds normal to me. I've had my 1.8 Corolla since April 2022 and i usually fill my tank when i reach about 40-48 miles left in the tank and i've already done around 400 miles. When i fill up the most i've ever put in is about 32 litres. There was another thread regarding this a little while ago but i can't find it now.

Edit, just found the thread, although it was over on the CHR part but the same applies to all Toyota's

 

[Dylanfan]

I don’t usually get much below a quarter but when I fill up the range shown is something like 540 to 560, I suppose that depends on how I’ve been driving.

[AndrueC]

Yes, that's normal for a Corolla and the same as the cars I had before it. There's no value in driving the car until it's running on fumes, in fact that's a recipe for disaster if you mis-judge it. Much better to keep a good reserve of fuel in case you might really need it.

I remember once on a French driving trip I was on my way home and I started to look for a petrol station because the gauge was below half. This was a Sunday and it turned out that most places were closed. Worse still this was in the early days of Chip & Pin when our cards didn't work abroad so I couldn't use the 24 hour stations.

I eventually found an open station by leaving the motorway and driving to a village (I guessed that village petrol stations were more likely to be open). But if I'd waited until the tank was nearly empty I might not have made it.

The extra weight of the fuel has a negligible impact on fuel consumption - we're only talking about a few kilogrammes.

 

[FROSTYBALLS]

Toyota tend to be cautious as regards fuel reserves. In the full owners manual, check the index for warning lights and 'low fuel light', and the referenced page should state approx how many litres remain when the low fuel light comes on.

Aside from that you really don't want to run out of fuel in a hybrid as the result gets rather expensive.

[forkingabout]

35 minutes ago, FROSTYBALLS said:

Aside from that you really don't want to run out of fuel in a hybrid as the result gets rather expensive.

As a work colleague found out in his hybrid Auris to his cost 😅

[WALLOP]

What problems are caused by running out of fuel in a hybrid as opposed to any other car?

[zx81]

Thanks all for the replies, just wanted to check it wasn't my car just being weird!

[FROSTYBALLS]

2 hours ago, WALLOP said:

What problems are caused by running out of fuel in a hybrid as opposed to any other car?

Toyota hybrids have not been designed to run without petrol. Running out of fuel can cause severe damage to the hybrid system.

[Nigelhj]

just my pennies worth,  I always fill up when showing half full, to wait until the tank is nearly empty risks sediment at the bottom to be drawn up into the fuel system and possibly clogging  the fuel filter.

I may be wrong as cars have  become more reliable and the build much better but go back a decade or more  it was certainly a risk then but I certainly would not let the fuel drop below 1/4 tank.

Regards

Nigel.  

[Cyker]

Toyotas are infamous for having a fairly large reserve, and it's not just the hybrids! Even my old Mk1 was like that; I remember after reading a similar thread on here years ago, I drove it on the last flashing bar to see how for I could get - Managed 100 miles before I bottled it and dove into a petrol station, but I still only got in 39L IIRC!  

 

The thing about not running out of fuel in a hybrid is because of the traction Battery - In a normal car, you run out of fuel, not a problem - Put more in, start it, away you go.

Problem with the hybrid is there is no starter motor. If you run out of fuel, the car can't charge the traction Battery, and if the traction Battery runs out, even if you refuel the car, the car can't start because the traction battery supplies power that starts the car...

And you can't use any of the normal techniques, e.g. jump-starting or bump/push-starting it, because there is no starter motor and the wheels don't turn the ICE directly like they do in a normal car.

 

In that situation, the car would have to be transported to a dealer, and then sit there for possibly months while they wait for the fabled and possibly mythical Toyota Traction Battery Charger to be delivered to the dealership, from whatever hallowed location it normally lives in, in order to put enough juice into the traction battery so it can start the car.

So it's quite a faff. Best not to run out of fuel and risk it in the first place!

The normal hybrids will shut down when you run out of fuel anyway, and won't let you drive on just the battery even for a little bit, to try and avoid this situation. In that case, you can normally just refuel it and start the car again, as long as it's not left so long that the traction battery runs out.

I'm not sure if this problem extends to PHEVs since they can charge externally.

 

[WALLOP]

That makes sense. So in theory as long as the traction Battery has sufficient charge to restart the engine at the point when you run out of fuel and you refuel within a day or so you should be o.k.