|
||
|
18th February 2019, 18:33 | #1 |
Gets stuck in
Rover 75 2004 Contemporary SE 2.5 Auto Join Date: Feb 2018
Location: Preston
Posts: 513
Thanks: 67
Thanked 56 Times in 46 Posts
|
M.P.G. readout...... how accurate?
Reset my MPG readout and decided to drive like a vicar on/around local roads(as usual),when I checked the readout it gave me 31.4 mpg...... Now this is a 2.5 Auto petrol monster machine........ normal readouts been anywhere between 20-25 on said same roads....
__________________
To have and not need, than need and not have. Eve was born on: Tuesday 14th September 2004 @ 07.54.23 Date of first Registration: Friday 24th September 2004 She was the: 103,715th 75 to run off production line, out of 112,381 She was the: 382nd 75 2.5 V6 Contemporary SE to be made out of 686 She was the: 1,415th 75 in Firefrost Red (code CEV) to be made out of 2,089 Firefrost Red 75's |
18th February 2019, 19:38 | #2 |
Posted a thing or two
Rover 75 CDTI Tourer Join Date: Nov 2014
Location: Great Bardfield, nr Braintree
Posts: 1,414
Thanks: 303
Thanked 436 Times in 317 Posts
|
The only way to check it is to do brim to brim preferably over say 1000 miles and then apply a correction factor to the OBD. Then you will be able to believe the mpg read out in the future.
|
18th February 2019, 20:05 | #3 |
This is my second home
ZT260 #243 (resting) Join Date: May 2010
Location: Prestonpans
Posts: 22,478
Thanks: 650
Thanked 4,624 Times in 3,358 Posts
|
If I remember correctly the mpg figure is an average over the last 100 miles or something like that. If you've cleared it will more or less give the current mpg. Its not that accurate anyway, highly optimistic.
|
18th February 2019, 20:29 | #4 |
Posted a thing or two
Rover 75 CDTI Tourer Join Date: Nov 2014
Location: Great Bardfield, nr Braintree
Posts: 1,414
Thanks: 303
Thanked 436 Times in 317 Posts
|
|
18th February 2019, 21:22 | #5 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
@m2n
The system is not as smart as many owners might imagine. You can coax virtually any average MPG readout you want, high, low, good, bad or indifferent. It all depends on how the car's been driven and how far, after the last reset. I made this one when I was trying to understand its logic. I have a 1.8T by the way not a seven litre Bentley. You did the opposite and got a surptrisingly good result. The mpg display will be reasonably accurate if you drive the car very consistantly over a lot of miles to allow it to aggregate fuel consumed and distance travelled. The computer algorithm should first be calibrated using real world data (brim-to-brim calculations) over a 500-1000 miles period driving in your consistant fashion. You calibrate the computer by following the notes given on the Trip Screen Diagnostic Mode here: https://www.the75andztclub.co.uk/for...ad.php?t=55585 You need Sections 5.0 and 20.0 plus the associated notes. If you want to see a consistant and realistic figure, never reset the OBD computer. If you do you'll have to wait 500-1000 miles again till the aggregation settles down. Doing this stops any unusual dragster type dash now and then from affecting the result. It gets 'diluted' with the large quantity of standard data. A change in driving style (say a different driver) would require a recallibration using their real world data. TC Last edited by T-Cut; 18th February 2019 at 21:25.. |
|
|