So I stumbled across a hilarious and frustrating thing earlier today, before anyone says anything I was literally on my way to the local garage to get diesel after a long journey yesterday.

 

I embarrassingly ran out of fuel in the back end of nowhere with what read on the needle as around 1/8th tank of fuel and 25 miles of range. I wouldn't normally let it get so low but as said before, I was on a long journey yesterday and was in a rush to get home on time.

 

I've heard of other vehicles having a fuel gauge calibration technique in vcds and I was wondering if anyone knew anything on this? It's not a huge issue but I'd like to fix it so if I ever end up in the same situation I could then trust the range a bit more! 

29 minutes ago, Xhuy10nx said:

I embarrassingly ran out of fuel in the back end of nowhere with what read on the needle as around 1/8th tank of fuel and 25 miles of range

I thought the vRS had a trip computer? If so then it's way more accurate than the gauge.

Yes, but isn't that the 'range'?

Aye, I find that the trip range on my 1.2 Ambiente is fairly accurate according to the MPGs I get (worked out using Fuelly on the 'net, with the brim to brim method).

 

Another solution is not letting the car get as low on fuel... but I'm not in charge of your life. So do what you like.

Think I've seen an adaptation channel in module 17, Instruments, so yes, something is tweakable. Can't remember details, have a play.

2 minutes ago, AnnoyingPentium said:

 

Another solution is not letting the car get as low on fuel... but I'm not in charge of your life. So do what you like.

I don't tend to, I left the house with 3/4 of a tank but didn't have my wallet and didn't fancy going home, getting wallet and going back out 

From now on treat 25 miles range as Zero range and 30 miles range as being near running out of fuel. 

https://www.vwvortex.com/threads/diy-adjusting-the-displayed-fuel-gauge-level-with-a-vag-com.3208286/  

There is an adaption channel but first check the sender unit both by measuring the fuel quantity near full and near empty using VCDS and also physically for a sticking float lever.

 

I always push the virtual reserve capacity to the limit but was caught out twice on my MK1 Octavia when the sender unit had stuck, both times when i looked at the trip reading I had gone to about 650 miles instead of the 600 or so when I would normally refill after driving 50 miles on zero range.

As mentioned there is a channel in VCDS, that vortex guide is good. It normally doesn’t need doing unless the car has had a fuel sender in the past or the sender has some how got damaged. Normally the fabia range meter and fuel gauge are very pessimistic for obvious reasons.

 

Fun fact: Fabia’s actually use the ABS controller to measure the vehicle acceleration/deceleration to compensate for fuel slosh in the tank

23 minutes ago, BilTechnik said:

Fun fact: Fabia’s actually use the AIRBAG controller to measure the vehicle acceleration/deceleration to compensate for fuel slosh in the tank

 

There FYP.

 

No accelerometers in the ABS controller.

You don't think you can measure acceleration by measuring wheel speed changes? 

32 minutes ago, Breezy_Pete said:

You don't think you can measure acceleration by measuring wheel speed changes? 

 

Why would you bother when you have X and Y accelerometers in the airbag controller so you can compensate for side to side as well.

 

However I doubt the function even exists since the gauge is heavily damped because because it's digital, not analogue and no doubt uses an average value anyway.

Fun fact:

 

You don't half see some BS on this forum! 🤣

8 minutes ago, J.R. said:

Fun fact:

 

You don't half see some BS on this forum! 🤣

Take your ABS fuse and go for a quick drive. You’ll notice a difference immediately, especially if your fuel is quite low.
Measuring acceleration with wheel speed rate of change is trivial. The gauge is damped but only slightly. If you accelerate or break the averaging time is increased to hide the affect of the fuel moving around. The airbag sensor isn’t used as acceleration data is broadcast on CAN. I wouldn’t be surprised however if the instruments also increase averaging time based on steering angle, although I haven’t tested that 

@Xhuy10nx Could your fuel level sender itself be faulty?

 

All this talk about adjustments to the fuel profile's seems a tad odd to me.

 

Easier said than done I'd admit, but I would be tempted to drain the tank and check values of what car thinks it has in the tank, I do believe most test plans say to add 7l or something like that and read again live values.

 

 

I am just an armchair mechanic that reads too much, so I could be off base.

You are spot on in my book, always look for the simple and obvious.

2 hours ago, BilTechnik said:

Take your ABS fuse and go for a quick drive. You’ll notice a difference immediately, especially if your fuel is quite low.

 

My ABS fuse has been removed for months because of a faulty wheel sensor that I can't be bothered to replace and the fuel gauge behaves exactly the same as before. It's steady as a rock regardless of braking/acceleration or sideways movement.

Edited 23 August, 20223 yr by TMB

5 minutes ago, TMB said:

 

My ABS fuse has been removed for months because of a faulty wheel sensor that I can't be bothered to replace and the fuel gauge behaves exactly the same as before. It's steady as a rock regardless of braking/acceleration or sideways movement.

Do have a ABS warning light with the fuse removed?

IIRC your car has a speedometer sensor on the gearbox, Lee, which may make a difference to the instrument cluster side of things?

And a constant warning buzzer as I remember? It’s possible you have a different ABS system or have removed a different fuse

Just now, BilTechnik said:

Do have a ABS warning light with the fuse removed?

 

Yes, abs light, engine malfunction light and red brake warning light.

Just now, BilTechnik said:

And a constant warning buzzer as I remember? It’s possible you have a different ABS system or have removed a different fuse

 

Warning buzzer gives three bleeps everytime the engine is started then stays off.

1 minute ago, Breezy_Pete said:

IIRC your car has a speedometer sensor on the gearbox, Lee, which may make a difference to the instrument cluster side of things?

 

Yeah, it does, Pete.

This thread just reminded me of my Talbot Sunbeam that had a moving coil type fuel gauge that would waver about all over the place with braking/acceleration The Fabia has the most steady fuel gauge of any car I've had.

I would prefer that, when it stops twitching on hard right (or left as the case may be) corners then you know that you really are about to run out of fuel.