Range Data Does Not Make Sense

[carolinel]

Has anyone else found the range data totally crazy? When I took it to the service department they said there was no problem and that all Yaris's were the same.

One day after the fuel light came on, I drove for only a few metres and then it told me I had 8kms available. I parked on the level, came out and then there was 0kms. What happened to the 8? Why did the numbers go down so fast after the bowser light came on? Is the light reading incorrectly (I doubt it) or is the range data wrong.

Another time I had just pulled onto a busy motorway when the petrol light came on and it said range 16kms. The range went down very fast and got to 0kms but I was stuck unable to get off the motorway, a tunnel and then a big bridge, before I could get to a petrol station. All on 0km range. It was very stressful.

A third event hapened where my husband had been driving the car, parked it in the garage and when I got into it and drove out the driveway into heavy traffic - it said 0kms! I drove to the nearest service station - now late for a meeting plus furious with my husband - and put diesel into the tank! Disaster. Had to miss the meeting, get towed home and told my husband exactly what I thought of him. But the car had had 20kms on the range when he parked it in the level garage. Where did the 20kms go?

If this is the case for all Yaris's then the purchasers should be made aware that the range indicator does not work or Toyota should fix it.

I have driven other cars where the range data has worked perfectly, coming down in a reasonable sequence.

Is this only my car - please assure me that others have found the same problem. If it is only my car, I will call the New Zealand customer service department and explain.

[FROSTYBALLS]

According to the owner's manual,

"The range represents the estimated maximum distance that can be driven with the quantity of fuel remaining. The distance is computed based on your average fuel consumption. As a result, the actual distance that can be driven may differ from that displayed. When only a small amount of fuel is added to the tank, the range may not be updated."

So two questions:

Have you zeroed your average fuel consumption? If you haven't, that may be affecting the estimate of the range.

Have you added small amounts of fuel when filling up? Generally adding 15 litres or less can result in the range not updating properly and giving erroneous estimates.

[Catlover]

It sounds like you always driving on a near empty fuel tank.

If so, thats not good practice, as any dirt in fuel will settle to the bottom of the tank and when you low on fuel you likely to suck dirt up in to system and eventually cause problems.

As for the fuel range data, I understand it works on the bais the computer logs your driving style and works out the estimated miles/km you could travel based on your current driving style. If you start driving with a cold engine then your fuel consumption is likely to be heavy and the reading will change to lower distance quickly.

Keep topped up with fuel and dont drive on the gauge would be my advice.

[Cyker]

You're better off looking at the fuel gauge than the estimated range numbers and using your brain tbh. It'll be way more accurate than the range computer, which tends to be over-conservative and easily confused. While there's nothing really wrong doing partial fill-ups*, it will confuse the computer even more.

* The whole thing about gunk buildup in the bottom of the tank is mostly bunk as the fuel is drawn off at the bottom of the tank! However, partial fuel ups can allow condensation to build up on the tank walls which can cause microbes and stuff to grow. This isn't so much a problem with petrol as it's pretty hydrophobic and is toxic enough to kill most microbes anyway.

Ethanol-blended petrol is a different matter as ethanol soaks up water like a sponge.

Worst is diesel as any water in the tank tends to form a layer between the air and the diesel which is a perfect breeding ground for any microbes which find their way in.

With diesel the myth is more true; While the gunk doesn't build up at the bottom of the tank, it does float on the top in that water layer, and if you run the tank too low the whole lot will suddenly get sucked into the fuel filter

(I always fill my tank all the way up to minimize condensation buildup in the tank!)

[Mike169]

Hi Caroline.

Like all previous posts partial filling up is not a good idea for reasons already given. The best way to calculate your mileage, i am not sure if you are using MPG (Miles per gallon) but to neck to neck the car when filling up and calculating the consumption is by far the most accurate and yes the onboard display can be a bit confusing as in reality hardly any of us constantly reset the computer to zero your average mile consumption. Any problems you know where we all are.

Mike.

[carolinel]

Hi Mike. We have never partially filled up. Only ever completely filled.

The reading is crazy: Why be on 18 or 20 kms when the bowser light comes on intially. We know it must be more than that!

Why does the figure disappear from 20 or other numbers when we park on the level, to zero?

We will set the average consumption to zero and see if it makes more sense then.

No - in NZ we use litres not gallons but it can all be worked out similarly.

Thanks for your support.

[FROSTYBALLS]

In the UK the fuel has been dispensed in metric measures (litres) for some years - but a programme of full metrification has never been completed. Only this year has the government decided to allow new road signs to show both metric and imperial measurements. So 'miles per gallon' (imperial not US) is still a widely used unit of consumption.

[Catlover]

Its nothing to do with partial filling Caroline, its more to do with letting the level go down too far before you replenish.

Even without the range data, which can only be treated as a guide as already said, you never know when you going to be stuck in traffic where you could be stuck due to accident or a breakdown and your fuel consumption drains your tank quicker then if you were moving as normal. Running low on fuel in such circumstances is self inflicted frustration and easily lead to arguments between couples, one blaming the other for not filling up.

Add to that, one poster mentioned condensation (water) being more when fuel level is low, means keeping fuel level in the tank is more beneficial.

And at the end of the day, low fuel levels, high fuel levels, you still got to put fuel in the tank if you use the car, so may as well relieve yourself of all woriesd and frustrations and keep higher levels.

[Mike169]

In the UK the fuel has been dispensed in metric measures (litres) for some years - but a programme of full metrification has never been completed. Only this year has the government decided to allow new road signs to show both metric and imperial measurements. So 'miles per gallon' (imperial not US) is still a widely used unit of consumption.

I think it's down to we don't like 'change'. In my head i still think in miles per gallon, my weight in stones and ounces, i measure in feet and inches and look up the weather temperature in Fahrenheit rather than Centigrade. I guess it's down to what generation you feel you are, what you were taught and what you are used to....................................a typical example would be someone would say 'This is a bag of sugar, it weighs 1kg', my reply would be 'Oh you mean 2.2lbs'..........showing my age now!

Mike.

[Devon Aygo]

Its nothing to do with partial filling Caroline, its more to do with letting the level go down too far before you replenish.

Even without the range data, which can only be treated as a guide as already said, you never know when you going to be stuck in traffic where you could be stuck due to accident or a breakdown and your fuel consumption drains your tank quicker then if you were moving as normal. Running low on fuel in such circumstances is self inflicted frustration and easily lead to arguments between couples, one blaming the other for not filling up.

Add to that, one poster mentioned condensation (water) being more when fuel level is low, means keeping fuel level in the tank is more beneficial.

And at the end of the day, low fuel levels, high fuel levels, you still got to put fuel in the tank if you use the car, so may as well relieve yourself of all woriesd and frustrations and keep higher levels.

As has been mentioned above the range is a "guestimation" based on tank level and average fuel consumption figures at that time. One thing that is always fixed is when the fuel light comes on there 10 litres of fuel left in tank so a range of 0 is not an empty tank. Toyota's rationale is that even with 0 range you should have more than enough fuel to reach a fuel station without issue.

[carolinel]

Yes I know we should put the petrol in before it reaches the light-on stage but in NZ and Australia (where we mostly drive) the petrol stations are certainly often way more than 10km apart but in the end your words ""Toyota's rationale is that even with 0 range you should have more than enough fuel ....." That is really my issue. Why have 0 range when that is not the truth?

But also why does ours change so dramatically, sometimes when we aren't even driving it?

Anyway - we'll carry on. We will fill it before we get near the light-on stage but continue to be amazed at a ridiculous instrument on the display panel that clearly does not make any sense.

Thanks for your comment. Happy driving.

[FROSTYBALLS]

"Toyota's rationale is that even with 0 range you should have more than enough fuel ....." That is really my issue. Why have 0 range when that is not the truth?

Which would you prefer?

Knowing that when the range does show 0, you're out of petrol and its time to either walk or call out the NZAA, AAA or RAA,

or that you still have a safety margin to use in getting to a fuel station.

[Devon Aygo]

Yes I know we should put the petrol in before it reaches the light-on stage but in NZ and Australia (where we mostly drive) the petrol stations are certainly often way more than 10km apart but in the end your words ""Toyota's rationale is that even with 0 range you should have more than enough fuel ....." That is really my issue. Why have 0 range when that is not the truth?

But also why does ours change so dramatically, sometimes when we aren't even driving it?

Anyway - we'll carry on. We will fill it before we get near the light-on stage but continue to be amazed at a ridiculous instrument on the display panel that clearly does not make any sense.

Thanks for your comment. Happy driving.

The reason Toyota set the system to have 10 litres of fuel left with a 0 range is they don't want you running out of fuel causing inconvenience to you and possibly damaging your car, working at a dealer you'd be amazed how may people still run out of fuel even when Toyota leave 10 litres in the tank when the light comes on.

The reason for a difference on start up there is a delay built into the dash dash display and fuel gauge, this dampens the effect of fuel moving around in your tank, As you drive the fuel moves back and forth in the tank without a damper the float moving up and down in the tank would have your fuel gauge jumping up and down and your range doing the same. So after parking it is possible for the level gauge to settle once the car has parked and on restarting the car for the dash to recalculate the range and level down a bit, the effect is exaggerated as the tank level drops.

[Mike169]

Hi Caroline.

A good point has been raised that when the reserve fuel light comes on you will have 10 litres of fuel left in your tank, now here's old imperial me but i am guessing your car does about 8+ miles to the litre? If that assumption is correct you will know when and if the light comes on you have 80ish miles until your tank is dry and if petrol stations are more than 80 miles apart then i can only suggest carrying and extra 5 litre fuel can secured in the boot....here in the UK we have the luxury of filling stations being more frequent. If it's any consolation i think the accuracy of the 'fuel estimator gauge' is a lot to be desired and the fuel tanks on the cars are too small anyway which i believe is mostly done so you can only carry less fuel which in turn reduces the cars weight when it is full of fuel which in turn means you will do and extra 0.01 (Very rough estimation) miles per litre which in turn makes the car more economical when compared to rival makes, personally i'd rather have a larger fuel tank. I have a Rav 4 myself and that too is much the same as your Yaris, my other car, an older E class Mercedes does almost twice the miles on a tankful of fuel purely as pro rata the fuel tank is much larger, yes it of course costs more to fill but it means i spend less time stopping off at fuel stations. It seems modern day cars are getting smaller fuel tanks purely i believe to save weight.

Take care, Mike.

[Madasafish]

My experience of fuel gauges which only showed empty when the engine stopped due to lack of fuel means I appreciate an advance warning.

After all, it gives you time to plan ahead.

I don't see why that is an issue.. And imagine the fuss people would make if the situation was reversed. Lawsuits by the score.

[Parts-King]

Range distance is only there for car salesmen to play "Fuel light Bingo" They take your demo home and see how far it can be driven without running out of fuel.........It is there for no other reason ;)