|
||
|
|
6th October 2019, 16:18 | #1 |
Regular poster
Rover 75 Tourer Join Date: Jul 2016
Location: Castle Donington
Posts: 41
Thanks: 12
Thanked 2 Times in 2 Posts
|
Trip computer questions.
A couple of questions about the trip computer thing on my 2.5 Connoisseur SE, the one that displays info on the Alpine radio head-unit thing or on the dash when I press the button on the end of the stalk;
1, How do I reset this? I expected it to reset itself when I zeroed the trip meter, but no. 2, Given that I've not reset it in 500 odd miles, it is wildly optimistic. It suggested that the car was giving in excess of 30 mpg, so I took it very easy to the end of the tank, by which time it was claiming almost 34 mpg! Thrilled? I'll say, especially when I calculated using a piece of paper, miles/(litres/4.54) = 24mpg. Do they all do that? Or have I got a drunken one? Or am I doing something wrong? Thanks in anticipation folks. |
6th October 2019, 20:40 | #2 |
This is my second home
Rover 75 CDTi Connoisseur SE & MG ZT Saloon 190 Join Date: Jun 2007
Location: Coven
Posts: 12,530
Thanks: 526
Thanked 1,877 Times in 885 Posts
|
Toggle to the MPG and press and hold in the end of the stalk to reset
__________________
www.midlandsnanomeets.co.uk Robs Car Gallery Coven near Wolverhampton WV9 2000 Cowley Built Rover 75 2.0 V6 Club SE/ Atlantic Blue/ Sandstone/Walnut (daily driver) 2003 Land Rover Freelander 1 TD4 HSE Helsinki Blue/Black Leather (swmbo daily driver) |
7th October 2019, 08:22 | #3 | ||
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,643
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Quote:
Quote:
Try this: fill the tank until the pump automatically shuts off. Wait five seconds then top it up until it shuts off again. Note the mileage and reset the mpg indicator to zero. Drive until you've used almost the entire tank then repeat the same brimming process and do the calculation. Compare with the figure on the trip computer. They should be within about 1 mpg of each other. Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
||
7th October 2019, 11:31 | #4 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,754
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
Following over a decade's discussion on this, it's apparent that 75/ZT OBD computers were calibrated over-optimistically in production. If you want better accuracy, it must be set correctly for the figures to reflect reality. The addendum to my Diagnostic Routine write-up shows you how to recalibrate it. But realise that significant variations in your driving style will skew the results, as will a change of driver. Above all, never reset the system after calibration or you'll lose the benefits of the computer's 'experience' - for want of a better word.
HowTo: https://www.the75andztclub.co.uk/for...ad.php?t=55585 TC |
7th October 2019, 12:04 | #5 |
Regular poster
Rover 75 Tourer Join Date: Jul 2016
Location: Castle Donington
Posts: 41
Thanks: 12
Thanked 2 Times in 2 Posts
|
A big thanks for your response.
I've been calculating the mpg of all of my vehicles since 19.10.11. I normally fill my tanks up to the second click of (generally) the same pump at the same garage. I use fuelly.com and it's really to give me an early warning of something about to go wrong. Here's the graph for my 2.5 litre 944. The big drop in mpg was when it was taken off the road for a bit of a re-build and was clearly just shunted about the workshop for a tankful. It's just odd that the on board consumption things on my XJ-8 and even my Vel Satis gave readings that were broadly inline with proper maths, but the 75 is just having a laugh. It will be used for a daily 26 mile commute over 4 junctions of motorway with dual carriageway at both ends. I'd hoped that it would easily do between 25 & 30mpg. Am I dreaming? |
7th October 2019, 14:43 | #6 | ||
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,643
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
I'd prefer to see the graph for your Rover KV6.
Quote:
Quote:
Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
||
7th October 2019, 15:27 | #7 | |
Regular poster
Rover 75 Tourer Join Date: Jul 2016
Location: Castle Donington
Posts: 41
Thanks: 12
Thanked 2 Times in 2 Posts
|
Quote:
I drove it a couple of hours home, pottered about in it, sorted a lack of kick down & drove it quite hard for a bit to ensure that it will be utterly reliable for my fair wife. Consequently, the graph is a little disappointing! This is the reality, the car continues to claim almost 34 mpg! |
|
7th October 2019, 16:23 | #8 | |
This is my second home
MG ZT CDTi Join Date: Jan 2014
Location: carrick
Posts: 7,859
Thanks: 3,494
Thanked 2,657 Times in 1,973 Posts
|
Quote:
If it hasn't been reset it will show the average mpg since it was last cleared, which could have been 10 years ago for all you'd be aware. My own consistently shows 20 per cent less than I actually get. In saying this, others as mentioned can get optimistic displayed claims. Sent from my SM-A600FN using Tapatalk
__________________
It is not gloss primer .............. it is duct tape silver! |
|
7th October 2019, 17:40 | #9 |
Regular poster
Rover 75 Tourer Join Date: Jul 2016
Location: Castle Donington
Posts: 41
Thanks: 12
Thanked 2 Times in 2 Posts
|
The fuelly.com graph tracks just 454 miles and gives an average of 22mpg - it's two brimmed full tanks - the car had three quarters of a tank when I bought it, I couldn't monitor my first fill up as I sent away the IPK? screen to have the lines removed and it reset the trip meter on the dash when it was re-installed.
I haven't reset the trip computer, but it zeroed itself either when the battery was disconnected whilst the timing belts were replaced, or when the head unit was removed & replaced. I suspect the former. The trip computer, this evening shows; Trip 2* - 622.6 Range - 521 Average - 33.6 mpg & Ave speed - 26.2 The distances are far too small for anything meaningful yet, but the disparity is huge. *I have no idea how to switch between trip 1 (assuming there is one) & trip 2. |
7th October 2019, 17:58 | #10 |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,643
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Dave,
It's clear from your useful posts that there are far too many variables involved to draw a reliable conclusion. The only way that you're going to judge your fuel consumption accurately is by abandoning the on-board display and the Fuelly software and replacing those with a brim-to-brim manual calculation over a full tank. I suggest that you do this when your wife begins her motorway & dual carriageway journey to work and report back with the result. That is the only way that you're going to get a figure which you can trust. Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
|
|