Re-fuelling: Fill to first-click, or to the brim?

flyingbananaskin

flyingbananaskin

Member
I tend to always fill to the first click, assuming this gives me the most accurate MPG as should always cut off at the same point. But being a 34L tank, I've never got even close to that and I do find the fuel gauge drops very quickly from the top which has that disheartening feeling(nonsense I know;)).

How do you lot fill up, to the first click, or do you go past that and just fill until it won't take any more?

And what effect should it have on sites like Fuelly that track your MPG(guessing it will spoil my tracking in the beginning if I change my pattern, but then become accurate again after a few fills of filling to the brim?)?
 
Filling to the 1st click isn't necessarily a reliable way of knowing you're always filling to the same point. The speed at which the nozzle dispenses fuel often has an effect on this. Those that spit fuel out faster can often trigger the click a little sooner than those that deliver at a slower rate.

I tend to fill up 'til it just won't take any more, but only if I'm then about to use a litre or more of fuel. As Dan_b recently said in another thread, leaving your car sat on a hot day with no space for pressure expansion is probably not the best idea.

I do this for 3 reasons:
1. I always know I'm filling to the same point which helps with mpg calculations.
2. I get more miles to a tank just by virtue of carrying more fuel.
3. I, like you, get disheartened by the needle falling almost as soon as you leave the petrol station. Silly, irrational and illogical, I know! But I can sometimes get 80 miles before I notice the needle's starting to drop. :D
 
Thanks timmus, interesting views. Think from my next fuel on I'm going to fill to the brim, rarely sits with a completely full tank anyway as car is always in use.

So am I correct in assuming my Fuelly calculations will be out for a few fuel-ups now? I guess I should change all the previous "full tanks" to partial fills(which I know don't returna accurate MPG calculations anyway) to bring me correctly in line.

Will be interesting to see how much extra I tend to add after the click, haven't done that in years(my previous cars have had much bigger tanks so first click was expensive enough as it was, lol).
 
Last edited:
I have no experience of Fuelly, so don't know anything about its limitations, sorry. I'm guessing it's not just a case of entering two values: litres purchased and miles driven!?
 
timmus said:
I have no experience of Fuelly, so don't know anything about its limitations, sorry. I'm guessing it's not just a case of entering two values: litres purchased and miles driven!?
Click to expand...

Have just altered them all to partial fill-ups, it still tracks you overall average, but doesn't give an MPG for each fill.

Still, over time I'll get back on track:)
 
First-click does not give you a reliable amount unless you always fill up at the SAME pump each time.

I always vent it & brim it. It gives you a pretty consistent figure. You have to make sure that you always use the same technique.
 
MikeMarsUK said:
First-click does not give you a reliable amount unless you always fill up at the SAME pump each time.

I always vent it & brim it. It gives you a pretty consistent figure. You have to make sure that you always use the same technique.
Click to expand...

Wow, just had a look at your fuelly entries, most comprehensive I've seen, good work!

How do you mean by vent it and brim it, fill to the click, remove the nozzle, then back in to fill to the brim?
 
These days I tend to fill to the first click, vent for about 5secs, then give it one more fill-to-click. That adds about an extra 1-1.5 litres without completely using up all the expansion space! I admit I also quite like that psychological effect of seeing how far you can go before the gauge moves.
 
flyingbananaskin said:
Wow, just had a look at your fuelly entries, most comprehensive I've seen, good work!

How do you mean by vent it and brim it, fill to the click, remove the nozzle, then back in to fill to the brim?
Click to expand...


He means he uses this (see pic).

I've never used this but i tend to try and put in the same amount of fuel each time, its not just your fill up that can effect your mpg's ie:- when your fuel light comes on do you fill up straight away?, do you drive for X miles and then fill up ? its all just an aveage or guid as to what i'm getting


Phil
 

Attachments

  • 27062009080.jpg
    27062009080.jpg
    392.1 KB · Views: 531
Yes, if you look at Phil's useful picture you can see a little button on the right hand side of the filler pipe, about 3cm in. This opens a vent leading from the expansion chamber in the fuel tank, so that the trapped air in there can escape. When you screw in the fuel filler cap, the cap itself opens the vent button.


I fill to the first click, then press this button with the nozzle, and then continue fuelling slowly after that. I stop when the fuel is literally at the brim, and any bubbles have gone away. There is around 3 extra litres of fuel.


The expansion chamber is mainly designed for petrol cars - petrol turns into vapour quite easily, so it needs a lot of space to expand. Diesel doesn't vapourise, it will expand very slightly, but not very much. In any case I invariably use at least a litre of fuel before the end of my journey. Hence if you're driving an FSI you should *not* vent, but a TDI is OK as long as you know you will be driving further.


As far as calculating MPG is concerned, it doesn't matter WHEN you refuel, you can refuel at the reserve, 60 miles into the reserve, or even half-way through the tank. The important thing is to fill up the tank consistently. I tend to do it when I'm well into the reserve (just to get more miles out of each tank).


For fuelly - if you fill the tank up (either to first click, or to brim, as long as it is consistent), this should be entered as a full tank, even if you refuelled half-way through the tank. But if you don't fill up the tank (i.e., put in exactly £20 or whatever), then it should be entered as a partial tank.
 
Last edited:
MikeMarsUK said:
Yes, if you look at Phil's useful picture you can see a little button on the right hand side of the filler pipe, about 3cm in. This opens a vent leading from the expansion chamber in the fuel tank, so that the trapped air in there can escape. When you screw in the fuel filler cap, the cap itself opens the vent button.


I fill to the first click, then press this button with the nozzle, and then continue fuelling slowly after that. I stop when the fuel is literally at the brim, and any bubbles have gone away. There is around 3 extra litres of fuel.


The expansion chamber is mainly designed for petrol cars - petrol turns into vapour quite easily, so it needs a lot of space to expand. Diesel doesn't vapourise, it will expand very slightly, but not very much. In any case I invariably use at least a litre of fuel before the end of my journey. Hence if you're driving an FSI you should *not* vent, but a TDI is OK as long as you know you will be driving further.
Click to expand...

ULP said:
The simplest method for acuracy is to brim the car so the fuel is level with the top of the nozzle but do not vent. This way it will never create an overflow problem on hot days and save for a tiny amount of expansion of fuel in hot weather it's the same amount each and every time.
Click to expand...

Very interesting, thanks everyone for the comments/opinions. Just need to decide which of the above methods I'm going to adopt and stick with(fill to the click and slowly continue until full, fill to click vent and continue to full, or fill to click continue to brim then vent and leave), probably make an on the spot decision at the pump later on:)
 
Last edited:
Filling up.

Hi Guys, I nearly always fill up at the same garage, same pump (Trago Mills Newton Abbot 132.8 today for unleaded) So I carry a small stick, hold the pressure realease button with the pump nozzle and hold the flap open with the stick then fill until the fuel no longer sinks. Takes a while but as there is 8 pumps there is not usually anyone waiting behind me. (I would hate to be) People are amazed that I have only managed to squeeze in 33.9l. Just did a hol to Birmingham, well Hockley Heath, it's nice around there, and got 47.89mpg over three tanks with a best of 48.02. I recon it takes about 5-6l more by doing that. Managed 359 ml on way home as refused to fill up at 142+ gong had been on since 337. Scary. I always do a few miles after filling so hope will avoid a pressure spill. Happy filling Cheers Colin.
 
Even scarier

Had to fill up again today, same pump, same method shock horror took 35.62 l. I knew it was low but must have been running on fresh air. Is this a record for a 34 l. tank? Would have filled up y'day but trago closes early on sunday and didnt get back in time. Colin
 
Impressive, 2 litres more than the most I've dared to go on my tank!

35 makes sense though, 34L is the size of the tank, so a bit extra for the pipe is to be expected.
 
wow thats impresive Colin. a braver man than me;) I normaly fill up just before the clackson goes off:eek: because it scares the living daylights out of me.

Thread swerve how is trago mills doing now? I have not been there for years. I remember they had a big fire there a few years back. I remember buying a cheap securty light there once. when I opened the box it was an expencive one with a cctv camra to attach to you tv:eek:

cheers

David
 
Re Trago Mills

Hi R.L. Trago Mills is much as it always was. Lots of rebuilding inc a huge new garden centre. As always you need to look carefully before you buy, but there are certainly some great bargins to be had. For instance Clear coat lacquer £2.49 for the same size as Halfords £7.99. And it seems to go on better. Petrol always cheapest around and its now Shell. Its now run by the son, who is almost as outspoken as his dad was. Lots of anti E U billboards on the way in. Lots of 'polish' or east europeans working there, or are they english who dont want to speak? They must have seen my posts and just dont want to waste half the day talking to me? Biggest problem with trago is the scrouts who go there for a day out with the badly behaved kids and block the gangways when you are trying to make a quick purchase. But I suppose that applies to anywhere these days. Regards Colin
 
Colin Shurvell said:
Had to fill up again today, same pump, same method shock horror took 35.62 l. I knew it was low but must have been running on fresh air. Is this a record for a 34 l. tank? Would have filled up y'day but trago closes early on sunday and didnt get back in time. Colin
Click to expand...

VERY brave man! Did you have a jerry can with you? The best I did was 33l.
 
Panic

No Humps, you can imagine I was bricking it. Couldnt even find an empty can to take. Just checked it was 346mls at only 43.79mpg, all short journeys on that tank. Mental note, next time put a fivers worth of the dear stuff in for peace of mind. Thought I could hear a pump ticking but convinced myself it was the blower. Must try and find a round can to fit inside the spare when I find a wheel to put my spare tyre on thats been in the boot since I had new tyres fitted. Regards Colin
 
I use the 1st click method each time, I generally use the same pump at the same petrol station to keep things consistent. I then put all the details into my iPhone.. did 58mpg on the last tank. Need a fill this weekend..
 
You must log in or register to reply here.
Back
Top