Re-calibrate MPG reading

[Mr Statto]

Is it possible to re-calibrate the MPG calculations in the display? According to Spritmonitor, mine is over-estimating by about 5% (average is shown as 46.9mpg, but it's actually 44.5) 

[penguin17]

21 minutes ago, Mr Statto said:

Is it possible to re-calibrate the MPG calculations in the display? According to Spritmonitor, mine is over-estimating by about 5% (average is shown as 46.9mpg, but it's actually 44.5) 

Yes it can be done via VCDS, possibly OBD11 too. 

[stanian]

It is possible yes.

 

Correction of fuel consumption in Maxidot
You can calibrate consumption if you see that it does not show what you think it should.

1 - Module 17 - Code Box instruments- (25327)
2 - Adaptation
3 - Select- Correc.del indic.de consumption / combustion scope - Options: (100%)
4 - Change value. Default 100%
5 - The adjustment allows increments of 1%, maximum and minimum values are 85 (%) and 115 (%).

[J.R.]

Mine was actually 13% over-reading, optimistic that is.

 

I put in the calculated correction factor 88% IIRC and it now matches spot on the brim to brim calculated consumption, will have to put it back or even further the other way if I ever decide to sell it!

 

In 14 years of my MK1 ownership it never dawned on me that the thing may have been lying or could be adjusted but whenever I did a brim to brim check it never corresponded

[Gerrycan]

When we first got our mk3 Octavia the consumption display (fuel tank average) was always a bit pessimistic by 0.1L/100 but over the last 58k km it has become optimistic by 0.15L/100. It does not seem to be tyre wear or tyre change related.

Not enough to worry about or do anything about and it is consistent enough for me to work to.

[Mr Statto]

OK, thanks. Looks like a pain in the arse to fix it, I'll just carry on knowing it's over-estimating a bit

[teescom09]

Tuning boxes and remaps often result in hugely overly optimistic mpg. The lies the box sends to the ecu from a sensor also becomes part of the mpg calculation  

[Gerrycan]

5 hours ago, teescom09 said:

Tuning boxes and remaps often result in hugely overly optimistic mpg. The lies the box sends to the ecu from a sensor also becomes part of the mpg calculation  

Certainly true of tuning boxes but was unaware that remaps would be affected?

[ChoonDoode]

I'm going to be doing this tomorrow, but can one of you just confirm this before I do it.

 

If it's reading 6.32% over (50.6mpg instead of 47.5%), I'd move it from 100% to 94% wouldn't I?

[Alex-W]

Oops, misread this

Edited 27 July, 2019 by Alex-W