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j_rov



Member Since: 10 Jan 2017
Location: Warwickshire
Posts: 311

England 
onboard computer mpg question

Hello guys

Does anyone know how the MPG is calculated on the on-board computer display? I'm running LPG but it still seems to calculate MPG even though no petrol is being used.

I know it's never accurate, particularly as my wheel size has changed but would be a useful guide.

Cheers

PS, getting 22 mpg on display (for a fairly sedate 50 mile A road run) which seems too good to be true! __

2000 4.6 V8 HSE Oxford Blue

Land Rover History:
2010 3.6 TDV8 Autobiography Stornoway Grey
2001 Discovery 2 TD5 GS
1999 Discovery 2 V8i XS
1994 Discovery 300Tdi
1993 Discovery 200Tdi
1989 Range Rover Vogue SE 3.5EFi
1976 Series 3 2.25
1977 Range Rover 2 door 3.5 Carb

Post #514779 9th May 2019 1:34pm
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Pawl



Member Since: 07 Nov 2017
Location: West Midlands
Posts: 449

England 2007 Range Rover Vogue TDV8 Cairns Blue

Are you sure you 're not using petrol during start up before it switches to lpg? Paul,
2001 Discovery 2 TD5, 201,000 miles & climbing
2006 FFRR TDV8 Vogue 133,000 miles & climbing
Member of Midland (Land) Rover Owners Club, www.mroc.co.uk

Post #514785 9th May 2019 2:24pm
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j_rov



Member Since: 10 Jan 2017
Location: Warwickshire
Posts: 311

England 

I'm positive it's using petrol initially, but the OBC seems to calculate "correctly" even when reset on LPG during journey. __

2000 4.6 V8 HSE Oxford Blue

Land Rover History:
2010 3.6 TDV8 Autobiography Stornoway Grey
2001 Discovery 2 TD5 GS
1999 Discovery 2 V8i XS
1994 Discovery 300Tdi
1993 Discovery 200Tdi
1989 Range Rover Vogue SE 3.5EFi
1976 Series 3 2.25
1977 Range Rover 2 door 3.5 Carb

Post #514800 9th May 2019 5:01pm
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Benfelrr



Member Since: 27 May 2012
Location: Wiltshire
Posts: 244

United Kingdom 2007 Range Rover Vogue TDV8 Tonga Green

I asked a mate who knows more about this generation of Range Rover than anyone else I know and he says...."Mpg... It work out distances traveled from odometer and then calculates fuel consumption from the engine ECU - I think from memory it counts the injector pulses so it knows how much fuel it's used, and then this with the distance traveled is used to get the calculations."

Hope that helps.

Your calculations may not be far out. My 2001 4.6 achieves 21 mpg on a steady (very) motorway run. Other than that whatever else I do day to day it sits at 17.1mpg all the time. It has the tornado (economy *cough*) chip in it. 2003 VW Golf V6 4motion
2001 Range Rover Vogue 4.6
1982 Range Rover in VOGUE
1990 Range Rover Vogue SE
2007 Audi A6 Avant Le Mans Quattro S-Line 3.0 TDI
2007 Skoda Ovtavia 2.0 TDI L&K
2007 GSX-R 750 K7

Post #514946 10th May 2019 10:51pm
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