Author Topic: Fuel Tank Reserve (Read 7078 times)

guest745 · « **on:** February 14, 2009, 11:03:15 PM »

I was just wondering what experience others had of the reserve tank on the Jazz.

Our old CVT seemed to indicate well over a gallon was left when the light came on - based on how much it took to fill the tank.

We have just had our second fill in the iShift and of course we now have a more sophisticated computer. I know these things are a little inaccurate. But experience to date is suggesting that the computer says the tank is empty when there is almost TWO gallons left - a bit more than the old model.

I was wondering if others had come to a similar conclusion with the new model ? Obviously we are not keen to try it to the limit to see if my initial conclusion is right.

It reminds me a bit of that Top Gear stunt, running from the south of France or similar up to Blackpool for the lights switch on (Polo Bluemotion, Subaru diesel, Jag XJ diesel). The Jag said the tank was empty somewhere past Birmingham but the car made it to Blackpool.

guest776 · « **Reply #1 on:** February 14, 2009, 11:14:05 PM »

can i ask how many miles you managed to get out of a tank before you filled it up?
I am just curious as the other half is picking hers up on the 1st of march a 1.4 EX Ishift

many thanks

guest745 · « **Reply #2 on:** February 16, 2009, 08:15:32 PM »

Hi Robla

I wouldn't go on our figures especially - we are 'hypermilers'.

We have had the car almost a month now and have just got our third tank in the car.

The first one we got about 59 on the computer which i reckon was about 56 real.

The second tank we got only 56 on the computer - it covered the period with all the snow and colder weather - plus her in doors did a couple of trips into town.

We have done 100 miles on the third tank and are showing 63 so far - but it will fall to nearer the 60.

At this level the tank should do 500 miles - but we need to ensure where we are with this reserve level - one gallon - or two ?

The reason why we get loads of mpg is that she travels 17 miles each way to work and back - from the outskirts of Scarborough to the outskirts of Malton. Its all fairly flat, rural and driven slowly without getting in any queues - 50mph is getting adventurous, but it spins up there quickly if you need to do an overtake (yes sometimes you do - but usually only tractors).

Then there is a weekly shop and not a lot else. Its the short stuff that kills the mpg - stop/start. Its still 10%+ better than the much loved CVT. And with only about 1000 miles on the clock the car will loosen - and the warmer weather will help further - what might we get - 65 is a definite target. The old CVT got 62 once on the computer but average was 55ish in summer.

Don't forget these averages are across full tanks - not little journeys - we can all get 75 on a small trip with the wind behind us (except in my old 2 ton Mercs

).

culzean · « **Reply #3 on:** February 17, 2009, 09:25:54 AM »

I have deliberately let the tank go down to the point where the fuel light comes on a couple of times. There still seems to be about 7 litres in the tank, bear in mind (same with most cars i've driven) that the first half of the tank always seems to drop more slowly than the second half. On the jazz this could be due to the amount of fuel in the long filler pipe to the tank or the fact that the second half of the tank takes account of the reserve amount and actually shows empty when there is still fuel in the tank.

guest745 · « **Reply #4 on:** February 17, 2009, 07:45:53 PM »

Thanks Culzean

I have noted from your previous posts that you are also a bit of a 'hypermiler'.

But admittedly we both have the benefit of longer journeys to get those mpg figures into the mid 50's or better.

Your 7 litres is on the old model isn't it ?

What seems odd is that the computer on the new models say - zero - miles left until next fill. This is different to 'you are in reserve and we think there is ?70? miles left till you run out - based on how you are driving at the present'

I suppose you can imagine the customers who are not as clever as ourselves and who would run dry by driving to the last ?5? miles. Plus of course there is the issue of any long term sediments that may build gently.

But as you say the second half of the tank seems to go quicker, whatever the car. My old Mercs only do one quarter of the miles on the last half tank - on the guage - but then there is still about 3 gallons left (50 miles to me - LOL).

At the end of the day we need to know that if the fuel light came on whilst she is on her way home one day she can easily go to work and back the next day without running out (say 50 miles) - if we haven't got time to get to the 'tax payment' pump overnight. If needs be I usually have a green can (or two) in the garage which I use to keep my other Honda topped up (125cc scoot - 90+mpg - carrying 18+ stone).