I bought my car new - RRS 2008 V8 petrol and have driven it fairly gently. My average fuel consumption has been about 16.2-16.4 MPG. I just bought the latest (2008/09) Nav disc direct from Navteq, put it in and it went into software upgrade mode. When it finished everything worked fine except my average fuel consumption was shown as 11.5 MPG.

Anyone got any idea about what happened?
I wrote to Navteq but they haven't answered yet.

Thanks

Geoff

Which figure is correct(ish)?? Cheers

Simon

2007 2.7HSE 20" Wheels
2005 TDV6 D3 S Auto - Zambezi Silver - JE Tune - RRS 19" - Sidesteps - Roof Rails
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I think that the first figure must be correct based on the car's computer doing a calculation of how much petrol I've put in and how many miles I've done over the life of the car? But I've never actually checked the accuracy - I just put in petrol when it needs it and believe the consumption read-out.

Perhaps something has caused a reset of the avg and the 11.5 is/was true over the new period/mileage?? Cheers

Simon

2007 2.7HSE 20" Wheels
2005 TDV6 D3 S Auto - Zambezi Silver - JE Tune - RRS 19" - Sidesteps - Roof Rails
Body Side Strips - Xenons - Bright Pack - Cold Pack - Premium Stereo
Alpine Roof - Towpack - Alpine Touchscreen Satnav - Veba Rear DVD changer
Alpine Roof Monitor - Webasto FBH Timer - Brembo Frt & S/C Rr Brakes

US gallon v imperial gallon? 2005 Zambezi TDV6 - Gone but not forgotten
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does it need recalibrating, I don't have a RRS, but in my FL2 it says to do it when you change tires ?

is it a really, really, really heavy disc .......I'll be off now Speed Limits! not where I live!

Back in a D3

Did have: RRS TDV8 2008.5MY
Did have: Q7 3.0TDi S-Line/Tech/Comms pack
Did Have: Disco3 HSE

Hmmm. The question about US or Imperial gallons is interesting. I bought my car here (UK) but it was originally destined for California so... if my car is telling me MP US G and it was 16.4 then that would equate to about !9.7 MP Imp G which seems to be a lot for a petrol car but I do drive it gently as I mentioned before.
Anyway, I phoned Harwoods in Basingstoke and they told me that my error was in leaving the engine running while the software updated (I should have turned on the ignition but not the engine). They told me to reset the MPG (I didn't know that it was possible but you just set the computer to show you the MPG and then push the button on the end of the stalk for a few seconds until the MPG shows dashes). I've done that. Tomorrow I'll drive it a bit until the MPG gives a reading and see what it says. I'll let you know.

Cheers

Geoff

OK then. I went out on a trip this morning, MPG reset to zero. After 1/2 mile numbers appeared - 5.5 MPG! But as I continued the numbers slowly increased until they finally reached 16.5 MPG and settled there. So everything is OK now.
Interesting that this is based on a US gallon and equates to 19.8 Miles per imperial gallon. My car was discounted by £18,000 (list price with options was £58,000 - I paid £40,000) because nobody would buy a petrol car in UK and the dealer was desperate to get shot of it, I've just calculated that on my average mileage of 7,000 per year and assuming 95 pence per litre I can drive it for free for 11.8 years or if I had bought a more economical diesel car for full price it would be... I dunno - 100 years or something before it started to be cheaper.
'course I'll get clobbered when I come to sell it but I don't plan to do that for a long time.

Cracking deal Geoff.

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Yes Supertrotter it's 4.4V8.

geoff wrote:

I bought my car new - RRS 2008 V8 petrol and have driven it fairly gently. My average fuel consumption has been about 16.2-16.4 MPG. I just bought the latest (2008/09) Nav disc direct from Navteq, put it in and it went into software upgrade mode. When it finished everything worked fine except my average fuel consumption was shown as 11.5 MPG.

Anyone got any idea about what happened?
I wrote to Navteq but they haven't answered yet.

Thanks

Geoff