Ibiza mk5 fuel tank and filling speed??

[loonymoon]

OK, so I'm lead to believe that the mk5 ibiza has a 45 litre tank, like my old Ibiza 1.4 used to.

So usually when I fill up I've done around 300 miles and the fuel light comes on at about 40 miles left. When I fill up with less than 30 miles left (sometimes closer to 10 miles left!) the pump clicks off with only about 40 litres filled so I think there's still fuel left in the tank (hence the range is better than my old 1.4)

However a couple of times, like the last time I filled up I had 288 miles on the clock with 30 miles on the fuel computer left, and the filler clicked off at 44.5 litres!! I can't have been that close to empty I'm sure??

I did notice that the pump was really slow and it took ages to fill. Once as an experiment I deliberately filled slowly having read somewhere that the pumps are more accurate as you get less vapour produced and the pump registered a similar amount for the fill (i.e. more than usual before the pump clicked off)..l.. so it does seem to be related to filling speed as I usually fill at max speed.

Does filling slowly end up with the same effect as venting the tank do you really manage to fill more fuel/less turns to vapour??

 

[DEAN0]

OK, so I'm lead to believe that the mk5 ibiza has a 45 litre tank, like my old Ibiza 1.4 used to.

So usually when I fill up I've done around 300 miles and the fuel light comes on at about 40 miles left. When I fill up with less than 30 miles left (sometimes closer to 10 miles left!) the pump clicks off with only about 40 litres filled so I think there's still fuel left in the tank (hence the range is better than my old 1.4)

However a couple of times, like the last time I filled up I had 288 miles on the clock with 30 miles on the fuel computer left, and the filler clicked off at 44.5 litres!! I can't have been that close to empty I'm sure??

I did notice that the pump was really slow and it took ages to fill. Once as an experiment I deliberately filled slowly having read somewhere that the pumps are more accurate as you get less vapour produced and the pump registered a similar amount for the fill (i.e. more than usual before the pump clicked off)..l.. so it does seem to be related to filling speed as I usually fill at max speed.

Does filling slowly end up with the same effect as venting the tank do you really manage to fill more fuel/less turns to vapour??

From 0 miles left on the computer I can get 54 ltr in to my FR TDi when venting - that gets me an average of 650 miles before filling up again.

 

[Dan_FR_DSG]

The same thing happened to me last week! The fuel light had just come on at 325 miles and still had a few more small bars to go. When I filled up the tank I was able to put 45 litres in the tank!

This completely screwed my mpg calculations. Either the capacity of the tank is larger than 45 litres or the fuel reading is inaccurate by quite a lot.

Also I managed to do 105 miles before the first light went down. If my readings are correct (which I don't believe they are) I will do 400 miles on this tank.

 

[loonymoon]

The same thing happened to me last week! The fuel light had just come on at 325 miles and still had a few more small bars to go. When I filled up the tank I was able to put 45 litres in the tank!

This completely screwed my mpg calculations. Either the capacity of the tank is larger than 45 litres or the fuel reading is inaccurate by quite a lot.

Also I managed to do 105 miles before the first light went down. If my readings are correct (which I don't believe they are) I will do 400 miles on this tank.

Yes the last time I got nearly 45 litres in the tank I managed 400 miles.... so perhaps the reading is accurate and normally I underfill/the fuel reading is underestimating the remaining fuel... I've never let it go down to 0 miles to test!!

 

[nightflight]

it's fine going down to 0miles left, furthest i've dared (had to) push it was 28miles, though tbh I was fairly shitting it by the time I limped into the petrol station.

 

[DEAN0]

Also I managed to do 105 miles before the first light went down.

I can get 225 before the first light goes off so it must be a characteristic of the tanks if you vent fill them.

 

[J400uk]

I find mine sits at full for ages and the last couple of bars last a long time also, its just the bit in the middle that drops quite hard! Always manage 400+ out of a tank though running it down to 0, record is 440.

 

[NetworkMan]

Hi Loonymoon,

I believe that there is a valve in the filler neck that is opened when the cap is fitted and the expansion space is then opened.

Two possibilities perhaps:-

1. You opened the valve in the filler neck with the filler gun without realising it - unlikely I guess.
2. The valve leaks air slightly so filling the tank very slowly enables the expansion space to be filled.

On my 1.2 TSI I usually do around 410 miles and then fill the tank quickly until the cutout works. This takes around 40 litres. It seems pretty consistent. The computer is then showing about 50 miles to go which is consistent with my usual 45 approx mpg. The book says that the warning comes on with 7 litres left but mine would seem to be more like 5 litres.

 

[MARKG_BOC]

I don't think my cars right I put fuel in 24 hours ago and not done no more than 12 miles and it's gone from 120 miles to 85 in 24 hours and that's only driving round town.

 

[Shelby]

it has a 45 litre tank, plus an extra 8 litre reserve, as mentioned in the book. venting the tank at fill up involves pushing the petrol pump along the right hand side of the filler opening, where you will see a switch - around the "3 o clock" position. that is the venting switch.
i have on plenty of occasions filled up 50 litres or more.
usually i get to around 150-180 miles before the first block goes out on the gauge. I can get to around 400 miles if im well behaved on mine - 1.2 Tsi DSG.
All in all rather respectable.

 

[adamb87]

I don't think my cars right I put fuel in 24 hours ago and not done no more than 12 miles and it's gone from 120 miles to 85 in 24 hours and that's only driving round town.

Yeah but the range is calculated by current consumption......

 

[loonymoon]

it has a 45 litre tank, plus an extra 8 litre reserve, as mentioned in the book. venting the tank at fill up involves pushing the petrol pump along the right hand side of the filler opening, where you will see a switch - around the "3 o clock" position. that is the venting switch.
i have on plenty of occasions filled up 50 litres or more.
usually i get to around 150-180 miles before the first block goes out on the gauge. I can get to around 400 miles if im well behaved on mine - 1.2 Tsi DSG.
All in all rather respectable.

Thanks. I have come to the conclusion that I have a heavy right foot and I've been trying concertedly to drive a little more economically lately. I've done about 45 miles on this tank of fuel so far, first block still showing on the guage and I've got 41 mpg average (1.2 TSI) on the overall guage (2) on the dash so far. My commute route is all 30, 40 and 70mph roads with a couple of short 50mph sections, I don't have any 60mph national speedlimit roads which means I'm either doing 70mph(+) or under 50mph so not in the most economical speed range. But I do also like to test out the acceleration of the tsi which is why I think I'm a bit heavy footed away from lights/roundabouts etc.


Anyone else noticed an effect by filling slowly vs quickly though?? I don't think I touched the vent switch when I filled up last time though I may have done without realising.

 

[NetworkMan]

it has a 45 litre tank, plus an extra 8 litre reserve, as mentioned in the book

Some confusion here I think.....

According to my book the tank capacity is 45 litres and a warning is given when there are (supposedly) 7 litres of those 45 left. The capacity is 45 litres, not 45+(7 or 8) litres.

There is an expansion space in the tank which is there so that if the fuel expands after filling due to an increase in temperature then it won't overflow. If you 'vent the tank' you fill this expansion space and then run the risk of an overflow. If you drive a significant distance immediately after filling there is little risk. If you park in the sun immediately after filling then there is more risk.

 

[Deleted member 67732]

Som
. If you park in the sun immediately after filling then there is more risk.

this is more significant with petrol than diesel.

 

[nightflight]

this is more significant with petrol than diesel.

but also more dangerous with diesel as diesel tends to shaft motorcyclists

 

[J400uk]

Some confusion here I think.....

According to my book the tank capacity is 45 litres and a warning is given when there are (supposedly) 7 litres of those 45 left. The capacity is 45 litres, not 45+(7 or 8) litres.

There is an expansion space in the tank which is there so that if the fuel expands after filling due to an increase in temperature then it won't overflow. If you 'vent the tank' you fill this expansion space and then run the risk of an overflow. If you drive a significant distance immediately after filling there is little risk. If you park in the sun immediately after filling then there is more risk.

Correct, 45 litre is really the maximum capacity and can only realistically be achieved with a bit of venting (which I get away with as the car covers massive mileage).

 

[loonymoon]

but also more dangerous with diesel as diesel tends to shaft motorcyclists

100% agree with that having come off my scooter on a diesel spill on a roundabout... bloody horrible stuff. It may not be such a fire hazard but it's certainly a slip hazard.

 

[buzz12chris]

Am I going crazy I've got a 1.6 tdi and only get 40 litres tops in it ( yes tried venting) and average 445 miles to a tank. Done 25000 miles and the economy is crap. Have taken it in 3 times with no help.

 

[NetworkMan]

Am I going crazy I've got a 1.6 tdi and only get 40 litres tops in it

What does the gauge show when you decide to fill it?
What does the remaining miles show on the computer when you decide to fill it?

40 litres over 445 miles is 50.6 mpg, not brilliant but there are several 1.6 tdi drivers on here who'd be quite pleased with that!

 

[buzz12chris]

I'm go down to 1 bar and it tells me 10 miles left have been down to zero. I do trips everyday between 50 and 70 mph roads. No dpf light since I've bought it. My other half has a new 1.4 copa done 2000 miles and getting 48.5 already. Has made me think about changing