Has any one else noticed how the fuel gauge needle can indicate almost to red then when I put in a feew quid of diesel the needle swings back up to 4 notches.  I find this very confusing

I wouldn't know.

I never do partial fuel-up.

I've not done a partial fill up but I do remember my golf doing something similar. I've also noticed it takes a lot of miles to get below half a tank but a lot less miles to get to empty...!

I've not done a partial fill up but I do remember my golf doing something similar. I've also noticed it takes a lot of miles to get below half a tank but a lot less miles to get to empty...!

Yes my Citigo is like that.

I haven't even done a first fill on the Rapid yet.

Fuel gauge on mine seems to be quite linear thankfully, so no nasty surprises (yet).

Thank you I have never filled mine, went to half full when I first put diesel in but since then I have usualy only put about £10 in a week (if that)  I dont use my car much.  3 500 miles last year.  1st time I have owened  diesel (was actualy cheaper than buying form a dealer at Motorpoint)  £12 000   1.6 SE 10 miles on clock when bought.  Last years B'day present.

Edited 4 September, 201411 yr by MarkRawlinson52

I've not done a partial fill up but I do remember my golf doing something similar. I've also noticed it takes a lot of miles to get below half a tank but a lot less miles to get to empty...!

 

Most cars I've owned have been like that. When full I think the amount of fuel is higher than the needle will go so it sits looking full for a while then slowly starts going down.

I've been very impressed with the maxi-dot accuracy, so it doesn't bother me how the needle moves to much.

Fuel gauge on mine seems to be quite linear thankfully, so no nasty surprises (yet).

Would agree with this, on previous cars that I have owned the fuel gauge had a tendency to drop like a stone once it hit half full.  This isn't the case with the Rapid however, and with the Maxidot giving figures very close to my own brim-to-brim calculations I find that I'm able to rely on the dials and information.

I've been very impressed with the maxi-dot accuracy, so it doesn't bother me how the needle moves to much.

 

Are you saying you trust the maxi-dot more than the needle?

I do...

My average consumption (measured in every refill to the top) is 0.4 lt/100Km higher (or 7.3% if you prefer) than that indicated in the Maxi-dot.

How can you know that?

Reset memory 2 when you fill up the tank, look @ what memory 2 says for consumption vs. the real consumption worked out when you fill it back up again.  My MaxiDot is mostly around 5% optimistic vs. what I actually get.  Weirdly, if I only do one or two very long trips and fill it back up at the end, the MaxiDot is a lot more accurate.

Mines very partial to a drop of fuel at the moment. Visually watching the gauge go down as you drive :(

But only on 630 miles at the moment.

Mine can go heavy on fuel when a regen is due. 

Fuel gauge on our Spaceback seems to be fairly realistic, as does the average fuel consumption on setting 1 (trip), which currently can read on a commute or long run between 47 and 52, depending on load and prevailing conditions. Last Fuelly figure came out at 49.2, this being the fourth tracked refuel since getting the car, first gave 45.2, then 47.3 and the third 48.1. Expecting it to now level out around 48/49, although I hope it may get into the fifties.

 

 

TP

Reset memory 2 when you fill up the tank, look @ what memory 2 says for consumption vs. the real consumption worked out when you fill it back up again.  My MaxiDot is mostly around 5% optimistic vs. what I actually get.  Weirdly, if I only do one or two very long trips and fill it back up at the end, the MaxiDot is a lot more accurate.

I've done this to measure the accuracy of the MaxiDot for my first three fill-ups.  Still finding the MaxiDot accurate to within 0.5%, with the average mpg marginally understated each time. 

Mines very partial to a drop of fuel at the moment. Visually watching the gauge go down as you drive :(

But only on 630 miles at the moment.

I know what you mean about seeing the needle visually drop! Things will improve as the miles mount.

How can you know that?

Actually I am a rocket scientist and did my post-doc in astrophysics and verification of actual consumption with trip computer.

.

.

.

.

.

.

.

.

Just kidding of course!

 

Your question was answered by Thecko: "Reset memory 2 when you fill up the tank, look @ what memory 2 says for consumption vs. the real consumption worked out when you fill it back up again." On the long run it's easy to measure accurately any discrepancies betweeen maxi-dot average consumption figures and actual consumption.

 

For example the consumption figures I got in the 5 refills I did so far (in 3700 Km) are :

1. 5.94 - 5.5 lt/100Km

2. 5.53 - 5.2 lt/100Km

3. 6.08 - 5.7 lt/100Km

4. 6.27 - 5.8 lt/100Km

5. 5.91 - 5.5 lt/100Km (actual consumption - maxi-dot avg consumption).

So by now, it's safe for me to say that the maxi-dot avg consumption is optimistic by approximately  0.4 lt/100Km or 7% (to be accurate I don't know which of the two applies).