What MPG are you getting from your Honda Jazz ?

[Jazzmeister]

I am having an issue with my Jazz 1.4 not with mpg, but with the mileage reading for the remaining fuel in the tank.
At 47k miles I was losing miles rather than gaining miles on the reading & it was incredible before that, so had the plugs & air filter changed & since then it hasn't been right. Had the tank breather pipe cleaned, but it is still an issue losing miles rather than gaining when doing 30 - 40mph for X amount of miles so the figure then increases.
Anyone else having this issue? What did you have done to sort this out? Many thanks

If you otherwise aren't having mpg fuel economy issues then just ignore it, it's just an indicator so doesn't actually reflect the engines health or running condition. Maybe just to be on the safe side record your fuel fill-ups and mileage to confirm the actual fuel economy is still acceptable and if it is then not much else to do.

[BrummPopBang]

If the mpg calcs from running the car from one full tank to another show an acceptable performance then you are ok.

I had a surprise with my ivtec Jazz where the aircon was on when it looked as though it was off. I had run it through the winter like this, so it was not obvious to me that the aircon was cooling until the first hot day about a three weeks ago.

This version has around LCD display about 50mm dia showing the temperature in the upper part of the display, the fan behaviour in the low part and across the middle it shows the state of the aircon ie...

A/C On
A/C Off
Blank

When showing blank, the A/C is ON. This caused dreadful fuel efficiency results but now that I habitually set it to A/C Off, the performance is much better.

[nigelr]

I have had my mk2 since 2018, just done my best run (Stockport to Llanwenog and back, 328 miles), up to 63 mpg, overall 60mpg. Normal mpg 48-52.

[Romel]

Last week from Liverpool - Folkstone - Gravesend - Liverpool

Was cruising in between 70-75 miles/hr in motorway with Air Con.
Average MPG 60 in motorway

Since last service 4800 miles, spark plugs renewal 2800 miles
Present mileage 85000

In city drive get around 44-46 mpg. Fuel light comes around after driving 320 miles in the city.

Jazz 2012 (1.4 Ltr engine), manual transmission.

[madasafish]

11 year results on my 2012 1.4 CT Jazz@ Fuelly
Mileage 58k. Mpg 42.7mpg
80% travel in town.

Recent 500 mile round trip to Scotland 50.1mpg.

[Brakballe]

My MPG is eggzellent! But it is OFC dependant about how ham fisted you are. I did some records recently with countryside roads driving. No HW (Motorways). Max speed was 80 km/h. Normal smooth, no egg under the speeder. 4.4 L/100km = 64.200227 mpg (UK)

[aphybrid]

I publish my mpg history in the MK4 forum.

After 'refining' my car settings to suit my style/comfort etc my overall consumption is 54.39mpg.

The chart and records indicate weather (temp) is a major factor and of course motorway usage.

Chart added for broader owners info.

[Marmoset]

and it roughly corresponded to what the computer said, so I decided to get a life and use the computer.

I found that the smoother your driving the nearer the computer is to real mpg.  Computer uses injector open times to calculate MPG and takes a snapshot every so many seconds to come up with average readout (the mpg readout responds to changes in driving much more quickly after you zero the trip display because it is averaging fuel used over a small number of miles,  as the mileage on the trip increase the updating gets more and more sluggish, until after 100 miles mpg average readout barely changes at all whether you floor the throttle or drive carefully).

http://www.greencarreports.com/news/1090929_gas-mileage-displays-in-cars-accurate-or-optimistic

That's definitely a Honda IMA dash in the above clip,  looks a lot like the Civic one with floating display and MPH reading just under the windscreen lower edge.

The last time I did a refill to brim-full tank test I only found a 1% difference.  My attempts to drive smoothly appear to be paying off!

Your point about the average MPG not changing much after getting a few miles into a tank is correct.  On the other hand, I've found the range to reduce far more quickly than the distance covered towards the end of a tank.  It's a little unnerving when you're low on fuel and stuck on the motorway. 

Still, I've managed a 1000km tank (though only in summer) and my accumulated MPG over around 16,000 miles is above 70.

[Skertonman]

New owner 1.2 vtec manual, full tank to empty, 33 ltrs to refill getting 345 miles, works out about 47mpg. Mixed driving including 150 motorway miles.

[stevieboyyyy]

On the other hand, I've found the range to reduce far more quickly than the distance covered towards the end of a tank.  It's a little unnerving when you're low on fuel and stuck on the motorway. 

Yes it plummet for me on a 362 mile journey (over two days) towards the end saying 35 miles remain and going down quickly!

Brimming the tank I could only get 32 litres in - so there was 8 to 10 litres still in the tank!

Quite annoyed as could have left it for the Mrs to top up as only had 25 miles to go.

Thoughts?

[Westy36]

Brimming the tank I could only get 32 litres in - so there was 8 to 10 litres still in the tank!

Quite annoyed as could have left it for the Mrs to top up as only had 25 miles to go.

Thoughts?

Our MK2 is exactly the same. The car often says distance to empty '0', yet only takes 32 or 33 litres. Yeah, they're all like that.

I believe the tank holds 42 litres, and given our car normally achieves 50pmg, when the distance to empty says 0, it probably still has a range of close to 100 miles! Even though I know this, I always go and fill it up just in case  On the plus side, at least we're not dragging the debris at the bottom of the tank through the filter that might cause problems.

[Lord Voltermore]

Same problem remains  in the mk4       I quite often set off with a satnav destination where I should have 100 range to spare. And i expect to be able to refuel more cheapy and conveniently  when I arrive    Yet before I arrive the car is now saying I have insufficient range.  I know there is probably still 5 litres left in the tank,  but I still get anxious.  I normally refuel when the fuel gauge drops from 3 to 2 bars. I only run on 'fumes' if I am really confident about the  local availability.   

I notice the Yaris and one or two other alternatives only have a 35 litre tank  so any problems or anxiety arrives that much sooner.

[JoeB]

My 2014 ex cvt 48k owned since June. Consistently shows 53 on the screen. Mainly a town car but a good few 100+ round trip motorway miles at 70mph and it still shows 53, sometimes slightly more or less. After a fill up reset shopping trip and a 10mile drive home it can be as high as 58 depending on traffic but soon slips back to the figure given once back to its normal habitat. Choosing the cvt was a surprise but for the driving i now do it suits perfectly. I have an MX5 to have a bit of spirited driving in so i just hope the Jazz lives up to its high praise.

[Westy36]

Great MPG from an auto.  I would take the cars reading with a pinch of salt though. Some call it the fibometer. Check how accurate by filling up, zero the trip. When you fill up again work out the MPG and see what you're really getting. Won't be that far out though. 

I don't check so often these days, but our wee Jazz manual always does 50+ unless the temps are <5c and we're doing a lot of town work.

[JoeB]

Your correct,  i knew it would not be truly accurate but as a guide it keeps you aware. Got rid of a 2019 Fiesta eco boom 125bhp i had from nearly new and that engine had all the praise lauded on it and for the most part deserved apart from its wet belt gaff. The Jazz is quite comparable indicated mpg wise but much less of a worry...........touch wood .