Author Topic: Cannot figure out why my Jazz MPG is so bad  (Read 3568 times)

nigelr

  • Approved Member
  • *
  • Posts: 49
  • Country: gb
  • 'Simplicity is the ultimate sophistication.'
  • Fuel economy: 51 mpg
  • My Honda: 1.4 ES
Re: Cannot figure out why my Jazz MPG is so bad
« Reply #15 on: December 01, 2018, 12:54:28 PM »
I know there are more economical cars around - but to me the Jazz is still a great balance of reliability, solidity and reasonable running costs - keep us posted how you go on!

kumarcherry2

  • New Member
  • Posts: 2
  • Country: in
  • My Honda: honda city
Re: Cannot figure out why my Jazz MPG is so bad
« Reply #16 on: March 18, 2023, 04:31:21 PM »
Hi guys!

I recently bought a 2007 Jazz SE 1.3/1.4 iDSI CVT from a friend of mine who had the car for 2 years, he went for a brand new jazz and sold me this one for almost nothing. I don't know much about the history of the car nor does he, apart from it was a cat C at some point, last serviced Nov 2017 (I'm servicing the car very soon), using oil 0w30 synth, air con dead, brakes were binding a bit, engine had a code for cylinder 4 misfire and a warning for running rich. As the car was cheap I thought it was worth the hassle.

Basically I fixed all the problems and engine issues, got new sparks in, changed 2 coils, clean the rest and swap them round. all the codes cleared and so far the engine has been fine. Also got my mechanic to check the engine and gearbox and he assured me they are in good shape. An gearbox specialist also checked the CVT and he also said it is good! Car also passed the MOT without any problems.

So I started driving the car as my daily, everyday I do 6 journeys of 4 miles each, I know this is not the best scenario for good MPG specially because the car has time to cool down between trips, but since I started calculating it, when I'm just driving around London, the Jazz is doing only 26 27 mpg which to me sounds extremely poor. About 250 miles range from a full tank. If I do the same with my Panda I can easily get 38-40, unless the weather is really really cold.

Anyway, the problem I'm having is that I don't know where to look from here and I can't afford to pay Honda to scan the car (150). Before I could blame the binding breaks, engine issues, but since I got all sorted I don't know what else to look for. The car seems to have the power it should and the MPG improves on the motorway. Done a round trip to Guildford with 4 adults in the car, going 65 70 mph most of the way and got 48 mpg. Last Saturday went to Birmingham and back, 2 adults, again going 65 70 mph, also tested a bit and car reached 85 without much struggle, in the end I got 53 mpg. These are actual mpg, not the trip computer, for some reason the trip computer is very optimistic in town and really conservative on the motorway.

The only strange thing I can see from scanning the ECU with Torque is that the engine load is always high, like if the car is idling and in neutral the load is at 34% and sometimes engine load simply stays off-line. But I don't know for sure if the Jazz has a load sensor or if this is a calculated number. Still strange I think.
 
Does anyone have an idea of what could be causing such poor mpg?

Big Thanks!
Hugo


Hi, I have the same issue too, mainly with the engine load, it is calculated based on MAP sensor and for some reason the pressure shifts to too low. Not sure if you have noticed due to it being CVT but it does lack pickup when you slow down in traffic with total hesitation

kumarcherry2

  • New Member
  • Posts: 2
  • Country: in
  • My Honda: honda city
Re: Cannot figure out why my Jazz MPG is so bad
« Reply #17 on: March 18, 2023, 04:32:35 PM »
Hi guys!

I recently bought a 2007 Jazz SE 1.3/1.4 iDSI CVT from a friend of mine who had the car for 2 years, he went for a brand new jazz and sold me this one for almost nothing. I don't know much about the history of the car nor does he, apart from it was a cat C at some point, last serviced Nov 2017 (I'm servicing the car very soon), using oil 0w30 synth, air con dead, brakes were binding a bit, engine had a code for cylinder 4 misfire and a warning for running rich. As the car was cheap I thought it was worth the hassle.

Basically I fixed all the problems and engine issues, got new sparks in, changed 2 coils, clean the rest and swap them round. all the codes cleared and so far the engine has been fine. Also got my mechanic to check the engine and gearbox and he assured me they are in good shape. An gearbox specialist also checked the CVT and he also said it is good! Car also passed the MOT without any problems.

So I started driving the car as my daily, everyday I do 6 journeys of 4 miles each, I know this is not the best scenario for good MPG specially because the car has time to cool down between trips, but since I started calculating it, when I'm just driving around London, the Jazz is doing only 26 27 mpg which to me sounds extremely poor. About 250 miles range from a full tank. If I do the same with my Panda I can easily get 38-40, unless the weather is really really cold.

Anyway, the problem I'm having is that I don't know where to look from here and I can't afford to pay Honda to scan the car (150). Before I could blame the binding breaks, engine issues, but since I got all sorted I don't know what else to look for. The car seems to have the power it should and the MPG improves on the motorway. Done a round trip to Guildford with 4 adults in the car, going 65 70 mph most of the way and got 48 mpg. Last Saturday went to Birmingham and back, 2 adults, again going 65 70 mph, also tested a bit and car reached 85 without much struggle, in the end I got 53 mpg. These are actual mpg, not the trip computer, for some reason the trip computer is very optimistic in town and really conservative on the motorway.

The only strange thing I can see from scanning the ECU with Torque is that the engine load is always high, like if the car is idling and in neutral the load is at 34% and sometimes engine load simply stays off-line. But I don't know for sure if the Jazz has a load sensor or if this is a calculated number. Still strange I think.
 
Does anyone have an idea of what could be causing such poor mpg?

Big Thanks!
Hugo


are you able to get this sorted?

embee

  • Approved Member
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  • Posts: 653
  • Country: gb
  • My Honda: 2018 Jazz SE CVT
Re: Cannot figure out why my Jazz MPG is so bad
« Reply #18 on: March 18, 2023, 11:01:00 PM »
error post, ignore
« Last Edit: March 18, 2023, 11:02:35 PM by embee »

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