jazz computer problem

[eljuero]

How do you comment this:


And there were still 4 l (0,88 galone) petrol left in tank.

Do you have the same problem?

[ThomP]

Wow!! That' a lot of kilometers on one tank of gas:-) My highest so far was 450 before the warning light turned on.

I have done some calculating to try to find out how the computer works, and this is what I found:
- The computer calculates the expected mileage based on ~33l; tank capacity minus ~10l
- Remaining kilometers are calculated using the EU norm (5,5 l/100 km) disregarding the actual consumption rate. I used to have the computer reset "A" after refuelling but just switched that function off to see if it made any difference.
- The computer is about 10% optimistic on the mpg calculation - according to discussions on www.fitfreak.net this is pretty much standard for the Jazz/Fit:(

So when the computer says you have 0 km left it just means you are on reserve. If my findings are correct you will have >10 l reserve. At 5,6 l/100 km you would then have ~4 l left after 100 km on the reserve!

I'm pretty annoyed with the computer: In my case, after refuelling the computer always says I have 610 km left. When I have driven 350 it says 150 left and when I hit 410 the light comes on. Basically this makes the computer completely useless for any purpose I can think of!

[eljuero]

Wow!! That' a lot of kilometers on one tank of gas:-) My highest so far was 450 before the warning light turned on.

Hehe..the same with me now but those pictures were taken shortly after I bougt it, when I was driving at low rpm 

I have done some calculating to try to find out how the computer works, and this is what I found:
- The computer calculates the expected mileage based on ~33l; tank capacity minus ~10l

Hm...interesting theory but check up this data:


I know that I have to add up 0,2 dcl/100 km on the AVG data.  So, 42:5,6 ... = aprox. 750 km with the tank (35 km driven + 718 km expected).
But coz intervals for calculating AVG of the tank and expected mileage are different you can get data as in the third line.
677 km with the tank based on AVG information vs. 841 km based on 69 km driven + 772 expected km.

I'm pretty annoyed with the computer: In my case, after refuelling the computer always says I have 610 km left. When I have driven 350 it says 150 left and when I hit 410 the light comes on. Basically this makes the computer completely useless for any purpose I can think of!

Yeah, I agree. That's why I expect Honda will repair it somehow. I clame the fault (that's why I have so much pictures of my car computer ) coz otherwise I will always have to fuel up full tank, otherwise I will lose control over gas data. Some months ago they reset and load updated software but without succes. I'm still waiting for their call, so they promised. 

[ThomP]

Hm...interesting theory but check up this data:


I know that I have to add up 0,2 dcl/100 km on the AVG data.  So, 42:5,6 ... = aprox. 750 km with the tank (35 km driven + 718 km expected).
But coz intervals for calculating AVG of the tank and expected mileage are different you can get data as in the third line.
677 km with the tank based on AVG information vs. 841 km based on 69 km driven + 772 expected km.

I don't get the last part - was trip A reset when you refuelled in the third line? Do you reset manually or automatically? I'm going to check mine the next time I refuel (first tank without the automatic reset) to see if it makes any difference to the way it calculates - like I said my expected mileage after a refuel has been 610/611 km every time without exception.

Yeah, I agree. That's why I expect Honda will repair it somehow. I clame the fault (that's why I have so much pictures of my car computer ) coz otherwise I will always have to fuel up full tank, otherwise I will lose control over gas data. Some months ago they reset and load updated software but without succes. I'm still waiting for their call, so they promised. 

Maybe the update messed it up instead of fixing it:)
I'm going to the dealer to get winter tires for the Jazz soon, and I will definetely complain about this - and I encourage everyone else to do the same. If Honda gets lots of complaints about this issue (assuming everybody has the problem of course) they might actually put an effort into fixing it!

[eljuero]

I have the reset function in mode "automatically". I just refueled this morning and of course I forgot to check computer for expected mileage. But after 3 km drive it was 650 km, AVG l/km was 10 l/100 km at that time.

What I want it to say in my previous post is, that computer recalculates AVG km/l on tank every X km and expected mileage every Y km. So using just simple math....

42l:6,2l=677 km, expected mileage of the tank base on AVG km/l information
and at the same time
841 km (69 km already driven + 772 km expected mileage base on ? information, definitively not AVG km/l)

.... doesn't always give the right answer.

Hehe...update just didn't work. But it's funny, so they told me, that Honda don't explain what is the contents of update. They only know later after updating.

I will contact my local Honda dealer again tomorrow to find out if anything is new. It's taking already to long now though I'm patient. Like you said, if we all do that, Honda has to do something.

[eljuero]

Just recieved negative answer from local Honda dealer. In their opinion there is nothing wrong, it's just the way it is . Like you were assuming, everybody has the "problem", so there is no problem 

But my car computer is still useless for that matter. Grrr..... searching for Honda international mails.   

[Rory]

I think the computer (in all cars, not just Jazz) is mainly for fun - it's not a serious tool.

Why is it a big deal, just fill up when the gauge tells you to?

[ThomP]

I think the computer (in all cars, not just Jazz) is mainly for fun - it's not a serious tool.

I don't know the "purpose" of the computer, but I know that a lot of people are monitoring their fuel economy. For those people it is a great tool to simplify the process - if it works. I don't know about "all cars", but in some cars it actually does work (it did in my old Renault Scenic), but in the Jazz it doesn't.

Why is it a big deal, just fill up when the gauge tells you to?

First there is the fact that people use the computer to monitor and improve fuel economy.
Second there is the principle that if a car is sold with a certain feature you should expect that feature to work - you paid for it!

[Downsizer]

My conclusion is that the software for the "distance remaining" feature was designed for a differently shaped tank, perhaps the Civic?  I find that if I set it to read miles, but think kilometres, it's about right!

[eljuero]

Why is it a big deal, just fill up when the gauge tells you to?

All together I'm very happy with my choice but Jazz has small 42l tank. Though I pass by the gas station every day I want to stop there only when necessary and not when my car computer start gauging me every few minutes and even gas scale shows zero gas though there is still aprox. 12l(!) gas in the tank. I can easily calculate my self the rest expected mileage base on the AVG l/100kms information (must add 0,2 dcl) if I have filled up full tank my last gas stop but psychological efect to run out of gas still works its own way.
 
I understand that car computer must be set to a specific reserve,  in Jazz case this should be 9-10l, which is btw almost 1/4 of a tank. But one of the reason I bought Jazz is its eko efficiency. Driving 30 and up kg less weight gives even better results, also accelerations.

So accurate information of expected mileage with the rest of the tank is kinda important to me. And of course I paid for working car computer functions a lot as well.

Anyone knows e-mail adress of Honda Europe coz it seems that this is major factury defect and local dealer won't do notning about it.

[culzean]

Eljuero, I am assuming that you are not an engineer, if you were you would realise (especially with cars and domestic appliances) that as a designer you can't please everyone because everyone wants something different.

I personally only use the trip and mpg readout to work out which driving styles give me the best mpg  readings, and never normally allow the fuel gauge to get below 1/4 tank before filling up.  Where the fuel light has come on I have found that I normally have about 7 to 8 litres left and thats fine by me.

Appreciate the Jazz for the well built, technically advanced and totally reliable car that it is and try to stop concentrating on small points and worrying too much - Enjoy!

[Geoffers]

I'm not impressed with the GE mpg computes. First fillup was 43.5 actual, 47 indicated; second fillup 37.4 actual 47.6 indicated!!!
My GD was never more than about 4 mpg diff!

[ThomP]

Looks like Honda actually addressed this problem:
http://www.sendspace.com/file/khux92
Let's hope it aplies to the European models as well

[ThomP]

 :(According to my dealer there is no update available for the Jazz:(

[eljuero]

No new update or no updates at all because my computer has been once updated already .