Roryboy Posted July 2, 2019 Share Posted July 2, 2019 I have a 2013 Pilote on a Ducato base 2.3 150 bhp and while fiddling about with the Menu I came across - Aver.Consump. B --- AcB 26.8 MP9 Is this the total average Mpg or just since I last filled the tank ? Any help appreciated. 8-) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 2, 2019 Share Posted July 2, 2019 This should be covered in the TRIP COMPUTER section of your Fiat Ducato Owner Handbook (refer to Index). The Trip Computer capability of a Ducato’s multifunction display permits two ’trips’ to be defined - Trip A and Trip B - and the calculations commence from when a new ‘mission’ is initiated by the driver using the TRIP control button. (I don’t know how the average (or instant) fuel consumption figures are produced. I doubt that fuel 'volume' is actually measured and I’m guessing that the consumption figures are just software calculations. Refuelling won’t affect the calculations.) Link to comment Share on other sites More sharing options...
weldted Posted July 2, 2019 Share Posted July 2, 2019 We have the same system when going on holiday reset B to give the total miles and fuel, reset A each time we fill up to see how that tankful goes. At the end of the day what fuel you use is the same as not recording it. We sometime set the range for a long trip just so when down to 50 miles fill up. Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 3, 2019 Share Posted July 3, 2019 Forget the dashboard MPG figures as they are inevitably unreliable. The only way to get a reasonably accurate figure for average MPG on a particular van, if that is what you want, is to record the mileage and the amount of fuel needed to fill the tank each time you fill up. It will wobble around at first, as factors such as traffic conditions, terrain, tyre pressures, wind speed and direction, ambient temperature, driving speed, and the point at which the fuel nozzle cut-off operates, will all affect apparent consumption. But, after a few thousand miles those should level out and the variations from fill to fill begin to coalesce around a reasonable average. Then, you can estimate how far you can drive on a full tank, and so the mileage at which you will need to refill. But even then, it will only represent your van's performance, based on where, and how, you drive it. Link to comment Share on other sites More sharing options...
aandy Posted July 3, 2019 Share Posted July 3, 2019 Brian, I don't know how typical it is but the trip computer on my Ducato is surprisingly accurate. I have checked it against the traditional method several times now, each time over a few thousand miles, and the results are generally less than 1mpg apart. The biggest difference I've seen was 1.5. Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 3, 2019 Share Posted July 3, 2019 I confess I gave up with the trip computer readings some time back, so it is quite possible that the accuracy has improved. I've been struck by the accuracy of the fuel gauge in our present van, so something seems to have improved! However, if using the trip, are you getting readings fill to fill, or over longer distances comprising a number of fills? The fuel consumption on our current van has varied between 31.79 MPG and 21.49 MPG (the latter being the result of a "top-up" fill of only 8.25 litres) for a single fill. But over 3,000 miles it has averaged 28.11, which is the figure of people probably need to work out the mileage at which they next need to fill. The longer the record is maintained, the more accurate it becomes. Link to comment Share on other sites More sharing options...
aandy Posted July 3, 2019 Share Posted July 3, 2019 Checks have always been around 2,000 miles. Though it varied over relatively short distances, if I didn't reset the trip for a thousand miles or more it was remarkably consistent, always ending up between 29 and 30mpg. That was what inspired me to check, as I didn't believe the consumption could be that consistent. Brimming the tank, zeroing the trip, then brimming again 2k later having noted what went in between times confirmed it. Earlier this year I noticed it was reading between 31 and 32mpg. Since nothing had changed I didn't believe it but, another check, this time just under 2000 miles, showed it to be accurate. As that was all done in France, and I tend to keep off the motorways, I did wonder if the reduced speed limit had something to do with it, but I can't see 6mph making that much difference. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 4, 2019 Share Posted July 4, 2019 This is the information that my Ducato’s Trip Computer can display TRIP A - Outside temperature - Range - Distance travelled A - Average consumption A - Instant fuel consumption - Average speed A - Trip time A (driving time) TRIP B - Distance travelled B - Average consumption B - Average speed B - Trip time B (driving time) I’ve no interest in the Trip Computer and, in order to decide when to refuel, I use the vehicle’s fuel-gauge as I’ve always understood that this is what that gauge is for. Link to comment Share on other sites More sharing options...
Billggski Posted July 4, 2019 Share Posted July 4, 2019 6mph reduction would make a big difference. That's about 10% slower, and wind resistance increases exponentially, especially with a large frontal area. https://www.mpgforspeed.com/ Link to comment Share on other sites More sharing options...
breakaleg Posted July 4, 2019 Share Posted July 4, 2019 There is an App called fuelio you can add as many vehicles as you wish, dosen't take long to fill in and gives you a very comprehensive read our I.E average mpg, cost best and worst etc.time line mileage log,Stats, charts,and much more Pete Link to comment Share on other sites More sharing options...
colin Posted July 4, 2019 Share Posted July 4, 2019 Derek Uzzell - 2019-07-04 7:48 AM I’ve no interest in the Trip Computer and, in order to decide when to refuel, I use the vehicle’s fuel-gauge as I’ve always understood that this is what that gauge is for. I also tend to use the fuel gauge to decide when to refuel, but I also leave the trip on 'range' as if say heading home on a tight margin and not wanting to stop, the gauge on lower markings can be misleading, for instance, if I've been light on the throttle at 1/4 tank I'll have a range of 200 miles, and the gauge will be in the red with still plenty of range. This is on the larger tank. Link to comment Share on other sites More sharing options...
aandy Posted July 4, 2019 Share Posted July 4, 2019 You're a braver man than I, Colin. The range prediction on mine can change by anything up to a couple of hundred miles in a very short distance. 200 miles can drop to nothing if you hit a series of uphill sections. OK if you're going home, where you know the terrain, but could be embarrassing in unfamiliar territory. Link to comment Share on other sites More sharing options...
colin Posted July 4, 2019 Share Posted July 4, 2019 aandy - 2019-07-04 8:19 PM You're a braver man than I, Colin. The range prediction on mine can change by anything up to a couple of hundred miles in a very short distance. 200 miles can drop to nothing if you hit a series of uphill sections. OK if you're going home, where you know the terrain, but could be embarrassing in unfamiliar territory. After eight years with the van it's sort of second nature to me knowing how the range is reacting and what the terrain is leading to my home, what I do know is if the low warning light comes on there is a good two gallons(if not slightly more) left in the tank. Link to comment Share on other sites More sharing options...
Steve928 Posted July 5, 2019 Share Posted July 5, 2019 Presumably the 'miles' used in an MPG calculation, whether that calculation is done by the on-board computer or by the owner recording fill-to-fill quantities, are the same 'miles' as used by the speedometer i.e. they are derived from wheel rotations and may be about 5-10% shorter than true miles depending on tyre size and state of wear etc? If so then many of us are getting less MPG than our chosen method tells us. Link to comment Share on other sites More sharing options...
aandy Posted July 5, 2019 Share Posted July 5, 2019 Steve928 - 2019-07-05 8:48 AM Presumably the 'miles' used in an MPG calculation, whether that calculation is done by the on-board computer or by the owner recording fill-to-fill quantities, are the same 'miles' as used by the speedometer i.e. they are derived from wheel rotations and may be about 5-10% shorter than true miles depending on tyre size and state of wear etc? If so then many of us are getting less MPG than our chosen method tells us. This occurred to me some time ago, so I checked. My speedometer over reads by about 8%, but when checked against GPS mileage the odo is accurate. I can only surmise that the inaccuracy in the speedometer comes from the final drive to the needle. Link to comment Share on other sites More sharing options...
Keithl Posted July 5, 2019 Share Posted July 5, 2019 The inaccuracy is actually designed into the software of the Instrument Cluster as the law demands that any speedo can only over-read the speed (by a maximum of 10%) but must NEVER under display the true speed. ie you can never inadvertently exceed the speed limit. I use an OBD style display plugged into my Sprinters diagnostic socket and thee speed reading on this unit matches exactly with the reading on my Garmin via GPS so the true speed is available but manufacturers have to 'fiddle' the figure to stay in line with the law. Keith. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 6, 2019 Share Posted July 6, 2019 Speedometer regulations are detailed in this Wikipedia entry https://en.wikipedia.org/wiki/Speedometer#United_Kingdom The UK-related section advises United Kingdom The amended Road Vehicles (Construction and Use) Regulations 1986 permits the use of speedometers that meet either the requirements of EC Council Directive 75/443 (as amended by Directive 97/39) or UNECE Regulation 39. The Motor Vehicles (Approval) Regulations 2001 permits single vehicles to be approved. As with the UNECE regulation and the EC Directives, the speedometer must never show an indicated speed less than the actual speed. However it differs slightly from them in specifying that for all actual speeds between 25 mph and 70 mph (or the vehicle's maximum speed if it is lower than this), the indicated speed must not exceed 110% of the actual speed, plus 6.25 mph. For example, if the vehicle is actually travelling at 50 mph, the speedometer must not show more than 61.25 mph or less than 50 mph. So, at a true 70mph, a speedometer could apparently provide a readout of 83.25mph and still be considered UK-legal. Interesting that your OBD-port-connected device provides a speed readout that matches that of a GPS sat-nav. I”ve sometimes wondered whether this would be the case and assumed that the OBD-connected device would produce similar speed data to the vehicle’s dashboard speedometer. There’s alot of on-line discussion about speedometer inaccuracy and ways to adjust the instrument, but Fiat has successfully sidestepped the problem for UK owners of 2006-onwards RHD Ducatos who drive abroad by deliberately making the speedometer unreadable in daylight. ;-) Link to comment Share on other sites More sharing options...
colin Posted July 10, 2019 Share Posted July 10, 2019 aandy - 2019-07-04 8:19 PM You're a braver man than I, Colin. The range prediction on mine can change by anything up to a couple of hundred miles in a very short distance. 200 miles can drop to nothing if you hit a series of uphill sections. OK if you're going home, where you know the terrain, but could be embarrassing in unfamiliar territory. Part 2 of my answer. As I normally have the 'range' displayed I think it's second nature to me to guesstimate the true mileage remaining compared to the range shown depending on expected terrain. On Saturday we where off to Southwold, gf had a 10p/lt coupon for Sainsbury's, we had under 1/2 tank and gf wanted to get the most from coupon and suggested we fill up on return, that's a return trip of 220miles (if no detours or trips out), on top of over 400 miles since we last filled up, range was showing 318 miles which I was confident was true, so in theory 98 miles in hand. Well on the return journey range was showing around 100miles in hand over the satnav 'distance to go' for most of the time with the odd high and low reading. A few miles from our home Sainsbury's a slight slog up hill with bends and traffic dropped range to 80 miles and low fuel light came on, but by time we got to Sainsbury's the range was back up to 102 miles, only 4 miles different from the original estimate. On filling it took 100litres then the max fuelling limit of pump kicked in which was before tank was completely full although it does now show full on gauge, it would not surprise me if there had been 20L left in tank. p.s. if I had managed to get 109L in that would make the trip mpg agree with the actual mpg, damn the 'max fuelling limit' on pumps. But as the gauge is showing full I'm sure I would have struggled to get that extra 9L in, and on the odd occasion I've check actual mpg with the trip mpg it's been pretty close. Link to comment Share on other sites More sharing options...
mgnbuk Posted July 10, 2019 Share Posted July 10, 2019 "Forget the dashboard MPG figures as they are inevitably unreliable." Certainly the case with the Mk8 Transit - that was always 2-3 mpg optimistic. Even more disappointing was that the "optimistic" figure was less that I was expecting and, according to a Ford technician, more than most Transit motorhomes achieved. The 2013 Ducato 130 readout was within 0.25mpg of calculated over a full tank & around 0.5mpg on a partial tank. My current Ducato 150 readout has always been so close to calculated values (just slightly pessimistic if anything) that I have stopped bothering with calculations & just go by the readout. The second set of trip values can be turned off in "Settings" (on a 2018 Ducato ) - I find one set enough & less to page through. Nigel B Link to comment Share on other sites More sharing options...
Guest pelmetman Posted July 10, 2019 Share Posted July 10, 2019 Roryboy - 2019-07-02 11:16 AM I have a 2013 Pilote on a Ducato base 2.3 150 bhp and while fiddling about with the Menu I came across - Aver.Consump. B --- AcB 26.8 MP9 Is this the total average Mpg or just since I last filled the tank ? Any help appreciated. 8-) My 1990 Transit can do 31 mpg ;-) ........ Cant say I'm bothered whether it does 21 mpg or less :D ....... We average 5k a year full time, so my fuel bill is peanuts compared to when I worked for a living B-) ......... The only shock to my income has come from moving down souf :-S ........ MOT & full service 2 years ago in Lincolnshire less than a 150 quid B-) ....... MOT & small service this year plus fitting upgraded headlight bulbs and a throttle cable (supplied by me) ...... £392 8-) ....... Link to comment Share on other sites More sharing options...
Guest pelmetman Posted July 10, 2019 Share Posted July 10, 2019 Derek Uzzell - 2019-07-06 7:42 AM For example, if the vehicle is actually travelling at 50 mph, the speedometer must not show more than 61.25 mph or less than 50 mph.[/b] Is that a typo Derek? ;-) ....... Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 11, 2019 Share Posted July 11, 2019 I don’t know if the Wikipedia information is correct, but if it is, I can’t see anything obviously wrong or illogical with the text you’ve quoted. Similar advice is given in the "The law for car speedometers in the UK” section of this link https://www.thecarexpert.co.uk/how-accurate-is-a-car-speedometer/ The law for car speedometers in the UK The UK law is based on the EU standard, with some minor changes. A speedo must never show less than the actual speed, and must never show more than 110% of actual speed + 6.25mph. So if your true speed is 40mph, your speedo could legally be reading up to 50.25mph but never less than 40mph. Or to put it another way, if your speedo is reading 50mph, you won’t be doing more than 50mph but it’s possible you might actually only be travelling at 40mph. To ensure that they comply with the law and make sure that their speedometers are never showing less than true speed under any foreseeable circumstances, car manufacturers will normally deliberately calibrate their speedos to read ‘high’ by a certain amount. Link to comment Share on other sites More sharing options...
Roryboy Posted August 5, 2019 Author Share Posted August 5, 2019 Many thanks for all the replies which have been most useful. :-D Link to comment Share on other sites More sharing options...
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