What MPG are you getting from your Mk1 Honda Jazz ?

[springswood]

"An ideal daily journey for an electric vehicle." And it's probably the driving most people do most of the time. However I think we sink so much money into our cars for that dream of the open road much loved by advertisers. I know I do 

As for Fuelly there are a lot of statistics, not certain how good they are. I was browsing all the data on Mk1 Jazzes and saw one tankful of zero mpg and another over 94. The devil is in the detail. Though to be fair the graphs exclude such outliers.

[Jocko]

There are some real numpties filling in data that skews the results. However, if you look at Jazz by year you get good data when you disregard the obviously spurious entries. Most statistical data disregards top and bottom groups using standard deviations.

[peteo48]

"An ideal daily journey for an electric vehicle." And it's probably the driving most people do most of the time. However I think we sink so much money into our cars for that dream of the open road much loved by advertisers. I know I do 

As for Fuelly there are a lot of statistics, not certain how good they are. I was browsing all the data on Mk1 Jazzes and saw one tankful of zero mpg and another over 94. The devil is in the detail. Though to be fair the graphs exclude such outliers.

I use Fuelly and I like a good pie chart and a graph. There is no doubt, however, that some members of the site are a bit lacking up top so you see Honda Jazzes with mpg figures of 25 to the gallon or, in one case, over 90 if I recall. I think people will often put partial fuel ups in and categorise them as full ones.

Garbage in garbage out as they say.

[springswood]

Very true. Though not everyone has an eye for detail.

For instance. I use a bluetooth OBDII dongle with Torque Lite on my phone. First, it's even more optimistic than the dashboard display. So only useful for indicating changes in consumption. One curious thing I've noticed is when say, going downhill off the throttle, the tiniest amount of pressure on the accelerator gives a better mpg figure than no throttle at all. Coasting in neutral shows better still (just out of curiosity, you understand). Typically 160, 110 & 80 US mpg. What I can't tell is whether this is real or just a quirk of how it calculates mpg. Possibly the latter, as it doesn't have much effect on the dash displayed figure. I do wonder if my throttle body or  some part of the emissions control stuff needs a clean. Of course if I do get round to tinkering with that I'll report results.

[Jocko]

I use the ScanGauge E, which connects to the OBD II port as well, but it is stand alone. It displays the instantaneous mpg(UK) and on a light throttle it will regularly display 90, 120, 170 mpg, and that is a real figure. If you think about it, to average 55 mpg for every minute you are doing 20 mpg you must also be spending a minute doing 90 mpg. And in a normal day's driving you will spend a lot of time doing less than 20 mpg (accelerating away in 1st for instance).
With the Jazz, when you lift off the throttle completely (provided the road speed keeps the engine revs up enough, 1800 - 2000 rpm), then the Jazz uses NO FUEL WHATSOEVER, in common with most other modern cars. This is called Deceleration Fuel Cut Off or DFCO. The ScanGauge indicated 9999 mpg. Coasting in neutral, with engine running and foot off the throttle requires petrol to keep the engine running, and I regularly see 200 - 400 mpg in this mode (depending on vehicle speed).
If your car runs smooth, and you have no management light, I would leave well along. The issue is with the software you are using.

[springswood]

That's just it, is my fuel cutting off but not being reported? I don't see why my OBD wouldn't get the message. More likely, with 112k miles, something needs a clean.

[Jocko]

Some software doesn't register DFCO. The software you are using doesn't even register mpg (UK). To have a failure that you are talking about would result in an engine management light. You wouldn't be seeing 54.8 mpg over 352 miles. My Jazz has done 114,000 miles and nothing needs cleaned.

[springswood]

Hmm. That 54.8 wasn't right, though I fill to the first cut off the tank before must have been very full and the one after not so much. My 42.3 average is OK I'm just looking round for what I might do to improve it.

[Jocko]

Had a fill up this morning, after 336 miles. I like to let tank get lower than that but I have an early morning hospital run tomorrow and didn't want the hassle of an early morning trip to the filling station.
I was surprised to see a calculated value of 53.8 mpg as I have had several high speed runs with rush hour crawls in between (as well as an "Italian Tune Up"). I have had no chance to drive for economy for a couple of weeks now. It looks like that figure could be easily achievable in a 1.2i-DSi, at this time of the year.

[Jocko]

Another short fill today. 334 miles and 25 litres. Gave me a very pleasing 61.4 mpg, which is all the more remarkable seeing this has been achieved in and out of Edinburgh, on a more or less daily basis.

[springswood]

Honest envy here 

[Jocko]

Yesterday, my wife had life saving surgery, and today I had a trip to Royal Infirmary of Edinburgh to visit her. However, I first had to visit her mother in The Western General Hospital. So I drove from Kirkcaldy into Edinburgh city to the Western, then a crawl, the 12 miles to the Royal, via Newhaven, Leith, and Seafield.
After a happy visit with my lovely wife I had another crawl to the City Bypass, then a smooth journey home to Kirkcaldy.
My ScanGauge E (which has currently been pessimistic compared to my calculated mpg figures) gave me 60.8 mpg for the 75 mile trip. The average speed was calculated as 28 mph! The Fibometer is currently displaying 64.9 mpg for this tank, so far.
I think the fact that most of my miles are single crewed at the moment, as well as the warm weather we are enjoying, have made a big difference.

[springswood]

Oddly the warm weather doesn't seem to have improved my mpg at all. Stuck around 42 mpg. Maybe it's time to try a tank of the good stuff.

[d2d4j]

Hi

This is my once and only highest figure I have managed.

Apologies for photo, taken whilst driving by my wife but the figure is showing 60.9 mpg at constant 62 mph by satnav speed using cruise control on motorway

Usually I attain anywhere between 46 - 54 mpg

I was happy at that figure but don’t think it was my driving. Just a fluke and yes, I know it’s a fibometer

Many thanks

John

[Jocko]

I only ever reset the Fibometer when I fill the tank, but it gives an indication of whether to expect good or bad figures when I do my sums.