Hi Guys,

New to the forum and new to the car which I have only owned for 2 weeks and already covered 1500 trouble free miles in! Safe to say I am enjoying the car.

My car (2006 model) seems to have optimism oozing from all of its instruments;

Speedo over-reads by 6mph, at 76mph on the clocks, my GPS says 70mph.

MPG computer over-reads by an estimated 11mpg!, I have calulated the average from my 3 fill-ups since owning the car, to be pretty much exactly 49 mpg, car thinks its doing 61 mpg!

Now Im not knocking 49 mpg, I think given that I am not cruising at 60 mph on the motorway, 49 mpg is a very good figure, especially considering the TDCI I used before the Fab only gave 45mpg on the same route. Its just that 61 mpg seemed too good to me :no: so I done the math!

Does the over reading speedo contribute toward the optimistic mpg displayed?

Having done a search on the issue, it appears the mpg can be corrected via the ecu, is this something which could be done at the same time as a remap for example?

Also, First half of the fuel tank seems to last for ever, 270 miles say, then the second half disappears! its like I have just transplanted the tdi for a V8 the fuel light comes on around 140 miles later! Is this usual for these cars?

Thanks in advance.

Hi Guys,

New to the forum and new to the car which I have only owned for 2 weeks and already covered 1500 trouble free miles in! Safe to say I am enjoying the car.

Also, First half of the fuel tank seems to last for ever, 270 miles say, then the second half disappears! its like I have just transplanted the tdi for a V8 the fuel light comes on around 140 miles later! Is this usual for these cars?

Thanks in advance.

First of all, welcome to the forums

Second, well done for completing a search on the mpg issue, whether it can be fixed or not, I don't know personally!

Thirdly, mine does the same on the fuel tank. Between 250 and 300, depending on driving and route, and then only about another 100-150 miles before the fuel light comes on. Again, driving and route dependent. I think the worst miles to a tank I ever had was about 370 when the fuel light came on, but this was during winter months, with leaking door seals which meant I was waiting stationary for 5-10 minutes for the windscreen to de-ice on the inside!!

All car speedos overread so your always 'safe'

Generally by 10%

All car speedos overread so your always 'safe'

Generally by 10%

Legally they are allowed to over read by up to 10%, but can't under read. Mine are usually 5% to 8% optimistic.

6 MPH out at 70 seems to be common on the Fabia, and many other VAG cars, lets not forget that tyre wear also affects the speedo reading as the overall circumference can vary by up to around 10mm depending on the original tyre tread depth as the tyre wears.

Thanks for the replies.

Yep appreciate all cars speedo's over-read, In my 16 years driving various marques/models I have found that some over-read more than others, just wondered if 6 mph over at 70 sounds about right for the model, which from your replies sounds like it is.

Bezzy; yep your miles per tank / fuel needle sounds very similar to mine so that seems about right too.

Cheers

your miles per tank / fuel needle sounds very similar to mine so that seems about right too

Most cars of different makes I've had do the same. (Skoda, Ford, Land Rover etc...)

I believe it's because when it's nearly full you know it's got loads... then it kind of becomes more accurate as you start to get low. Either that or it's designed to shock you so you remember to fill up.

In terms of actual miles driven, half full in reality is usually about 60 to 65% full according to the display.

My speedo is the same- I will do the 'math' when I fillher up next! Hopefully I'm not too disappointed :(

MPG figures look fine. As for the MPG computer, it calculates using injector quantity over time and is way over optimistic as you have discovered. It can be trimmed down using VCDS, but not worth the hassle. With new tyres my speedo reads 74MPH when the actual GPS speed is 70MPH.