Last time when the low fuel warning fired up, the range counter showed 100km. In fact it just dropped from 110 to 100km when it went off. I was on a highway doing 130+ km/h. Tonight, while driving in the city at 50 km/h, it fired up at 95km, but not immediately after dropping from 100 to 95km. So, is the low fuel warning based on the range and the current consumption (and/or speed) or the quantity of fuel left in the tank?

The car is Octavia MK3 FL, 16 TDI@115.

 

Additionally, i have noticed that when the range is 100+ kilometers, the resolution of the counter is 10km. When the range is less then 100km, the resolution of the counter becomes 5km. Also, for the AdBlue range the resolution seems to be 500km.

 

5 hours ago, damjanev said:

So, is the low fuel warning based on the range and the current consumption (and/or speed) or the quantity of fuel left in the tank?

 

 

I have noticed similar in my 2.0tdi.  Could well be a function of fuel remaining, current consumption and recent driving style.  I've had it go at 85miles and also at 50.  Was on 65miles on the way to work this morning but no bingbong yet.

It’ll be based on how far the remaining fuel quantity can get you at the current consumption. 
 

So, let’s say for the sake of argument it comes on with 1 gallon of fuel left.  If you’re currently running at 40mpg, your distance to empty with show 40 miles. 50mpg, 50 miles and 30mpg, 30 miles and so on. 

@SC03OTT I think we are talking about slightly different things.  You are talking about how it calculates the remaining range.  We were talking about when the warning fires to say you have low fuel.

3 hours ago, MarkyG82 said:

@SC03OTT I think we are talking about slightly different things.  You are talking about how it calculates the remaining range.  We were talking about when the warning fires to say you have low fuel.

 

He is saying the same thing.  The low fuel comes on when you have a certain amount of fuel left, not when there is certain range left.  So if you on a motorway it will come on at higher range left, in town it will show less miles.

40 minutes ago, Kental said:

 

He is saying the same thing.  The low fuel comes on when you have a certain amount of fuel left, not when there is certain range left.  So if you on a motorway it will come on at higher range left, in town it will show less miles.

Haha, thanks. I was totally struggling with how to reword my answer. 

I get it now but I think it is the reverse of what you are saying.  'Shirley' the more economic you are (say 50mpg)it will come on later as you are able to cover more with a set amount of fuel left.  Or are you saying it always comes on when you have 1 gallon remaining so 50miles @50mpg or 30@30 etc. like you said.  It seems to be more variable than a simple calculation based on having 1 gallon remaining.

1 hour ago, MarkyG82 said:

I get it now but I think it is the reverse of what you are saying.  'Shirley' the more economic you are (say 50mpg)it will come on later as you are able to cover more with a set amount of fuel left.  Or are you saying it always comes on when you have 1 gallon remaining so 50miles @50mpg or 30@30 etc. like you said.  It seems to be more variable than a simple calculation based on having 1 gallon remaining.

I don’t think range is based on trip average, but last few miles. 

3 hours ago, Kental said:

I don’t think range is based on trip average, but last few miles. 

I wasn’t asking about the range, but the low fuel warning light. 😉

1 minute ago, damjanev said:

I wasn’t asking about the range, but the low fuel warning light. 😉

 

In all cars I have low fuel warning light is fuel amount not range so yes will vary

Not the fuel amount but iirc it pings when 55miles worth of fuel remains.

And yes it changes. Set off from Buxton down the long A6 dual carriageway descent.  Foot off loud pedal. And when I arrived at the bottom, predicted range was 75 miles.

Later in the trip, heavier mpg reduced range back to 55 miles again and ping . Kia have remaining fuel range as well as VW group.

Edited 22 November, 20196 yr by gregoir

3 minutes ago, gregoir said:

Not the fuel amount but iirc it pings when 55miles worth of fuel remains.

My 1.4TSI (same as gregoir) pings when there is 40 miles range left?

 

Several years ago on another forum there was a similar discussion, one member had contacts at Audi and was told the range was based on the amount of fuel left and the average consumption over the last 20 miles.

 

This would explain how the range can increase after a fill up and gregoir's comment about the range increasing after a long descent (where the consumption will have been very low or even zero if the fuel cutoff was operating).

 

I've seen the range increase by 100 miles after a fill up meaning that after doing 50 miles I had 50 miles MORE range than when I started!

Edited 22 November, 20196 yr by PetrolDave

Mine fires at about 50 miles of range left. Sometimes that means the fuel gauge is into the red, sometimes not.

i stand corrected.

Fuel light coming is not based on range left, it comes on when there is about 7 litres of fuel left in the tank. driving style, speed etc does not come into it, just the magic amount of 7 litres left.

8 minutes ago, Ju1ian1001 said:

Fuel light coming is not based on range left, it comes on when there is about 7 litres of fuel left in the tank. driving style, speed etc does not come into it, just the magic amount of 7 litres left.

 

Thanks. This is what I was thinking hence the difference in range depending on car usage.

How you were driving and if you were averaging 30 mpg or maybe coasting lots & getting and indicated 60 mpg does make the difference to what the 'Range' shows when the 7 litres or whatever is left and the light comes on.

My fuel light came on as I happen to be driving to the petrol station.

 

I filled up 41.51litres.

1 hour ago, Culinia said:

My fuel light came on as I happen to be driving to the petrol station.

 

I filled up 41.51litres.

 

Mk3 has a 50lt tank I think. So filling 41.51lt is close to the mathematical volume.

 

Edit:

41.51 + 7 + a touch for the drive to fill up.

Edited 23 November, 20196 yr by MarkyG82

The 'Tank Capacity' does not include the 'Up the pipe and brimming capacity.

That can be another 7 litres.

38 minutes ago, Roottootemoot said:

 

That can be another 7 litres.

 

I didn't realise it could be that much!

Managed to put 67.5 litres in a 60 litre tank once, I had done 810 miles though.

 

Don't think that filling a petrol up to the spout is good practice.

It can muck up the fuel tank carbon vent filter. EVAP.

 

Thanks AG Falco