What MPG are you getting from your Mk1 Honda Jazz ?

[Jazzmeister]

I'd been barely getting 40 mpg, quite a bit of pinking and flat spots so I decided to change the spark plugs. Since I'm keeping Bob the Jazz a good while I treated her to some iridium plugs. Flat spots and pinking gone and even on my short dog walking trips the dash shows 47 mpg. I suspect the better spark from the iridium plugs is making the difference.

What was striking was the plugs that came out (photos attached). Looks like only one of the rear coil packs was giving much of a spark. I wish now I'd kept close look on what I was doing as I don't know which is the good one. I had actually fitted a secondhand set of coils got cheap on eBay. Now I've put back the originals as they're younger though still suspect as the rear plugs weren't changed when I got the car. Now I'm tempted to get some new coils. If they got me 2 mpg more they'd pay for themselves in a year or so. At least if I get cheapest ones - there's a bewildering array of brands and prices with no idea if any are better than another.

I can't see the gap but even those rear sprakplugs don't look too bad barring some mild fouling.

[springswood]

Agreed. I felt the poor running suggested a weak spark so swapping the plugs seemed a reasonable first step. The gap was fine, the canonisation on the insulation was the worry. A little extravagantly I've put new coils in. Yesterday in fact.

It's too early to know the effect on mpg but I have realised there used to be a slight vibration through the steering wheel on tick over which is gone.

To confuse matters even more it seems I had a rear brake sticking, maybe only for the last week or so. That is now fixed so I hoping for good things.   

Certainly seems to run nicely now.

Anyone any ideas what I can do with a load of slightly worn coils and plugs 

[Jocko]

Today is my 4th anniversary of owning the car and part of the process is topping off the tank. It was a short fill up as I had only done 283 miles on this tankful. The mpg figure was 59.6 compared with 61.8 on the Fibometer. I have averaged 55.5 mpg for the 40,070 I have completed since purchasing the car.
For the past year, I have averaged 215 miles per week and a cost per mile of £0.16p.

[peteo48]

Great stats. I bet not many Jazz (or Fit) owners will have bettered these.

[DomnicZZ]

Jocko. You are the undisputed MPG king!!!

I finished my first full tank at 49 MPG (52.7 Fibo) Took me almost 2 months to complete, as I don't drive much. I still think 49 is decent for a 16 yr old CVT. I attribute a lot of it to using my bike for short journeys when I'm travelling alone. Good for environment and health.

I've used momentum99 in the last tank. This time I've used regular unleaded but popped in some redex. Not sure if it helps but at 2 quid a bottle,  I'm happy to pay for the placebo effect  once in a way. 

Next upgrades will be changing to 0W30 oil, and some molybdenum disulphate that I know of thanks to this forum.

[Jocko]

Next upgrades will be changing to 0W30 oil, and some molybdenum disulphate that I know of thanks to this forum.

I use 5w-30 and recently have topped up with 10w-40. I do use Redex, now and again. My ScanGauge E has paid for itself, giving me a clear understanding of what works and what doesn't when it comes to fuel saving.

[culzean]

Jocko. You are the undisputed MPG king!!!

I finished my first full tank at 49 MPG (52.7 Fibo) Took me almost 2 months to complete, as I don't drive much. I still think 49 is decent for a 16 yr old CVT. I attribute a lot of it to using my bike for short journeys when I'm travelling alone. Good for environment and health.

I've used momentum99 in the last tank. This time I've used regular unleaded but popped in some redex. Not sure if it helps but at 2 quid a bottle,  I'm happy to pay for the placebo effect  once in a way. 

Next upgrades will be changing to 0W30 oil, and some molybdenum disulphate that I know of thanks to this forum.

Redex or similar even more important on low annual mileage cars, whatever you do don't put MoS2 in CVT box  - OK in engine though ( in fact the Honda Jazz piston skirts are already coated with MoS2 - molybdenum disulphide as part of friction reducing, together with roller bearings in tappets, cam followers etc. ). 

[peteo48]

The low mileage cars thing is something I ponder over - my annual mileage is around 3,000 and a lot of that is urban stuff. Even without any engineering background it seems common sense to me that carbon and other deposits will build up quicker in an engine that spends rather too much of its time below operating temperature.

I guess the issue is whether a tank of V Power (or similar) every other tank will have the same effect as an additive.

[Jocko]

I have said before, I have run umpteen cars on supermarket fuel and never put a drop of Redex in any of them, and never had the least bother. I have had cars that ran 5 miles to and from work every day and others that did 80 miles, mainly motorway, to and from work every day. I have sold cars on with 200,000 miles plus on the clock and never had engine problems. Now if V-Power and Redex stopped them rusting, then I would be interested.

[Derkie54]

The low mileage cars thing is something I ponder over - my annual mileage is around 3,000 and a lot of that is urban stuff. Even without any engineering background it seems common sense to me that carbon and other deposits will build up quicker in an engine that spends rather too much of its time below operating temperature.

I guess the issue is whether a tank of V Power (or similar) every other tank will have the same effect as an additive.

Like you my annual mileage is low, and like you I have recently bought a shining grey Mk3.
I can accept everything Jocko says but for the mileage I do I'm happy to put some V Power in if it keep the engine cleaner and the carbon deposits down.......well that's what they claim !!

[culzean]

I have said before, I have run umpteen cars on supermarket fuel and never put a drop of Redex in any of them, and never had the least bother. I have had cars that ran 5 miles to and from work every day and others that did 80 miles, mainly motorway, to and from work every day. I have sold cars on with 200,000 miles plus on the clock and never had engine problems. Now if V-Power and Redex stopped them rusting, then I would be interested.

I do use Redex, now and again.

If redex will 'melt' the petrol residue off old bike carburetor  that has been building up for ages ( makes you realise how dirty petrol really is ) I am not against putting it into petrol tanks on bikes and cars ( and even keeps lawnmower running sweet,  and it actually starts in the spring without the carb needing a strip down ),  its cheap enough - now if it was as expensive as printer ink  ( weight for weight the most expensive stuff on the planet ).

[peteo48]

I have said before, I have run umpteen cars on supermarket fuel and never put a drop of Redex in any of them, and never had the least bother. I have had cars that ran 5 miles to and from work every day and others that did 80 miles, mainly motorway, to and from work every day. I have sold cars on with 200,000 miles plus on the clock and never had engine problems. Now if V-Power and Redex stopped them rusting, then I would be interested.

I do use Redex, now and again.

If redex will 'melt' the petrol residue off old bike carburetor  that has been building up for ages ( makes you realise how dirty petrol really is ) I am not against putting it into petrol tanks on bikes and cars ( and even keeps lawnmower running sweet,  and it actually starts in the spring without the carb needing a strip down ),  its cheap enough - now if it was as expensive as printer ink  ( weight for weight the most expensive stuff on the planet ).

Good point about printer ink. To replace the ink cartridges in my HP Ink Jet printer is around £30 (for the colour and the black). I paid £35 for the printer. It's the equivalent of petrol being £1000 a gallon - probably more!

[Jocko]

Filled up this morning, and as is my practise I reset the trip (only one on the Mk1).
I returned home from the supermarket then took out cat to the vet in Dalkeith, a 90-mile round trip (don't ask).
On my return, the "Fibometer" was indicating 73.4 mpg.

[Jocko]

I topped the tank up today. Supermarket 95 RON. The light hadn't come on, but I have a few miles planned so thought I might as well fill up. I had covered 466 miles since the last top-up, the "Fibometer" was saying 64.6 mpg, and Fuelly's calculated figure was 62.0 mpg. This is my best figure during the previous 12 months.
The "Fibometer" was only 4.2% optimistic.

[DomnicZZ]

Amazing figures Jocko. This tank I started off rather well, maintaining 60 on the Fibo for the first 100miles,  thanks to longish country road trips and 40psi in the tyres. I've since lowered my tyres to 36psi front and 32 rear (experimentation). I'm now hit with the 1.5 mile school run which has been a disaster to my MPG, brought me down to 54 on the fibo, so I've lost hope of reaching last tanks figure.  In the colder months to come, I figure I'll be lucky to get above 50.