Hi all,

 

Anyone else having problems with inaccuracies that their car is telling them when it comes to range. Doesn't matter about real mpg when it is complete guesswork when driving it.

 

My car is currently telling me 0 range when the fuel gauge is half way through the red!. Plus when I run the fuel gauge right down to the bottom of the red (and I mean right on the bottom white line below the red). When I fill up it only takes 45 litres. I'm seriously loosing at least 50mpg from my max due to inaccurate measuring.

 

Is there anything I can do to reset either of these myself as I've got another 6k before it's due another service and will attempt to get the dealer to look at it again. 

 

 

43 minutes ago, Novascape said:

Hi all,

 

Anyone else having problems with inaccuracies that their car is telling them when it comes to range. Doesn't matter about real mpg when it is complete guesswork when driving it.

 

My car is currently telling me 0 range when the fuel gauge is half way through the red!. Plus when I run the fuel gauge right down to the bottom of the red (and I mean right on the bottom white line below the red). When I fill up it only takes 45 litres. I'm seriously loosing at least 50mpg from my max due to inaccurate measuring.

 

Is there anything I can do to reset either of these myself as I've got another 6k before it's due another service and will attempt to get the dealer to look at it again. 

 

 

 

It is a VW thing.

Zero miles left is about 48 litres and there is still 2 or 3 litres left i find. 

Done 10 miles past zero a few times and close to twenty on one occasion and others have done up to 40 miles.

Renault just blank the display when it gets down to about 50 miles just as bad.

 

What is worse one cannot so easily fill the expansion area like I could on earlier Skodas.  Should have left the tank at 55 litres IMO.

Edited 7 January, 20197 yr by lol-lol

Managed to do 40+ miles tonight on 0 range and still had 5 litres in the tank 

10 hours ago, Novascape said:

Managed to do 40+ miles tonight on 0 range and still had 5 litres in the tank 

 

Sounds like the VW system says Zero when there is still a couple of litres left at least, a different variant on the Renault system of just removing the figure all together.

 

Fuel injected cars do like getting down below the last 5 litres.  Crud in the tank and cavitation damage to pump if air starts to get in the system.

Local Tescos has water in its diesel fuel which is usually discovered when the tanks get low.

 

Think I will stick with refuelling when it gets down to last 20 miles or so.  Would like to use Momentum fuel like I did with Fabia 2 VRS but cannot justify it with the single charge 1.4 rather than the twincharge.

I very rarely let any car get down to very low fuel level because I do not trust fuel gauging at the lower end of the scale.

I know the 'safe' range of my cars and usually fill up asap when I get to the 'safe' range limit.

Having said that - we live in a small town with only 1 filling station so we tend to just top up when we are near Tesco etc in our nearest big town.

Our other car is an 05 CR-V diesel and on Xmas day  I had to go into Perth to pick up daughter,so decided to give the CR-V a Chrimble treat and went round to BP  and filled her up with some of their super super ultimate diesel as a one off - ordinary diesel for the rest of the year LOL.

Most manufacturers show the light when there is approx a gallon left in the tank. 

I don't know what peoples obsession is about knowing about every last drop there is left in the tank.

 

Because the systems in place for measuring fuel tank level and mpg are not accurate by any means, and because people in general are stupid, manufacturers have to build in a safety factor into when the light comes on and how many miles are remaining on the MFD, can you image the uproar if somebody ran out of fuel while the MFD was still reading 5 miles left, there would be hell on.

 

I know it would be really nice to be able to make use of all the fuel and leave it till the very last few litres but its not possible to get a reliable enough reading to do so.

It would be near impossible to get 100% accurate. It’s not like the fuel flow is constant. You’re constantly changing speed and acceleration.

 

Like the poster above, I’m curious as to what the obsession is. 

22 hours ago, Novascape said:

Hi all,

 

Anyone else having problems with inaccuracies that their car is telling them when it comes to range. Doesn't matter about real mpg when it is complete guesswork when driving it.

 

My car is currently telling me 0 range when the fuel gauge is half way through the red!. Plus when I run the fuel gauge right down to the bottom of the red (and I mean right on the bottom white line below the red). When I fill up it only takes 45 litres. I'm seriously loosing at least 50mpg from my max due to inaccurate measuring.

 

Is there anything I can do to reset either of these myself as I've got another 6k before it's due another service and will attempt to get the dealer to look at it again. 

 

 

I believe you may be able to adjust the readings with VCDS.

2 hours ago, SuperbTWM said:

I don't know what peoples obsession is about knowing about every last drop there is left in the tank.

 

Because the systems in place for measuring fuel tank level and mpg are not accurate by any means, and because people in general are stupid, manufacturers have to build in a safety factor into when the light comes on and how many miles are remaining on the MFD, can you image the uproar if somebody ran out of fuel while the MFD was still reading 5 miles left, there would be hell on.

 

I know it would be really nice to be able to make use of all the fuel and leave it till the very last few litres but its not possible to get a reliable enough reading to do so.

 

Yes, the obsession with the "range" reading really annoys me. It increases when your on the motorway, and generally drops quite quickly after you've fueled up.

Not the range that is really ****ing me off. It is the fuel gauge telling me I have absolutely nothing left in the tank but when I fill up it only needs 45 litres until I'm full.

 

I am never using over 1 gallon ever! That is over 60 miles in my 1.6. My total range has never gone over 560 miles as I have always been to scared to push it with the risk i could run out in the middle of nowhere.

 

I just want my dashboard gauge to be accurate. It should not be well below the red mark right on the bottom and still have 5 litres in the tank. I could understand 1-2 litres left but over 5 

53 minutes ago, Saints92 said:

 

Yes, the obsession with the "range" reading really annoys me. It increases when your on the motorway, and generally drops quite quickly after you've fueled up.

Agree   

Edited 8 January, 20197 yr by sandman

2 minutes ago, Novascape said:

Not the range that is really ****ing me off. It is the fuel gauge telling me I have absolutely nothing left in the tank but when I fill up it only needs 45 litres until I'm full.

 

I am never using over 1 gallon ever! That is over 60 miles in my 1.6. My total range has never gone over 560 miles as I have always been to scared to push it with the risk i could run out in the middle of nowhere.

 

I just want my dashboard gauge to be accurate. It should not be well below the red mark right on the bottom and still have 5 litres in the tank. I could understand 1-2 litres left but over 5 

 

Better that way than the other way round though Novascape 

Out of all the problems you could have with your car - a 'safe' and under reading fuel gauge system really is the least of your worries,I agree with others on here that there can be a tendancy these days to obsess a little about 'range' - 560 miles is a reasonable range anyway.

I never plan to take my tank much below 1/4 and very rarely take it below that.

2 hours ago, Novascape said:

Not the range that is really ****ing me off. It is the fuel gauge telling me I have absolutely nothing left in the tank but when I fill up it only needs 45 litres until I'm full.

 

I am never using over 1 gallon ever! That is over 60 miles in my 1.6. My total range has never gone over 560 miles as I have always been to scared to push it with the risk i could run out in the middle of nowhere.

 

I just want my dashboard gauge to be accurate. It should not be well below the red mark right on the bottom and still have 5 litres in the tank. I could understand 1-2 litres left but over 5 

 

5 litres is not a lot of fuel. when you look at the footprint of an average fuel tank its basically the dregs in the bottom.

 

Also, if you think there is 5 litres in there i'm willing to bet there's probably 10, if you can only get 45 litres in by brimming it.

 

I'm not sure if there would be a way to frig the fuel gauge with VCDS but you could always do a ghetto gauge calibration. Just take the needle off and replace it a wherever you want. 

Edited 8 January, 20197 yr by SuperbTWM

10 litres  think I'm going to have to get myself a canister and run it dry to work out how far I can go once the gauge tells me it is empty.

 

It's a company car so I've got to make ever mile count  plus I don't have a single cheap petrol station near me so would like to have the confidence to know I have enough fuel to last me until I travel somewhere cheap.

 

 

2 minutes ago, Novascape said:

10 litres  think I'm going to have to get myself a canister and run it dry to work out how far I can go once the gauge tells me it is empty.

 

 

 

 

You're not the first person on here to do this, can't remember who it was now but it was on a PD engine which are pretty resilient as there is no HPFP.

 

Running a HPFP dry on a modern common rail is a really bad idea. 

It was me!

 

Gone through many tanks since then and have worked out how it functions.

 

A full tank will drop to around 3/4 full before the needle will drop from the full mark, its plain geometry and pretty much every car I have had has been like that.

 

If you dont change your driving style then the miles remaining on the display when you fill up will be pretty much exactly how many miles you can drive before running out, lets say it says 600 miles to make it easy.

 

You will drive 100 miles + before the fuel guage drops from the full mark but the range will have dropped to 500 miles, still accurate at this point, its probably not even worth looking at the fuel guage until it gets down to the last 1/4 but the miles remaining will still be accurate.

 

Over the last 1/4 of the tank the miles remaining will drop faster than the miles you are actually doing, this is to ensure that when the guage shows zero there will be a reserve of at least 5 litres remaining.

 

At 1/8 of a tank the low fuel warning light will come on and the range will show exactly what your average mpg is, say 55 miles, but after you have driven say 25 miles it will then show zero miles.

 

Drive antil you run out and you will have covered the exact number of miles +/- 25 miles of what the range showed when you filled up.

 

If you reset both the trip and the average fuel consumption during the first 100+ miles it screws up the range calculation, it thinks the tank is still full, you may have driven 100 miles out of a range of 600 but its likely to show you having another 700 miles available, it will correct itself gradually and be as normal at 1/8 of a tank.

 

The most accurate thing is to always brim the tank carefully, reset the trip odometer, look at how many miles it says your range is which will be accurate, say its 600 miles, remember that and keep your eye on the trip odometer, you can be confident that you should fill up ust before the 600 mile mark if your journey and driving profile dont change.

 

The fuel warning light is much more insistent on my MK2 Octavia than on the MK1 as it flashes and is annoying, as a consequence I dont run the tank as low.

 

If you always refill at 1/4 of a tank its an awfull lot of unecessary fuel stops over the life of a vehicle but its an individual choice, I like to know exactly my range so as not to be stressed by the warning light and zero miles remaining showing on the display when there are no fuel stations around.

Edited 8 January, 20197 yr by J.R.