Fuel tank filling?

[sports racer]

All the reports say the fuel tank in the Cupra has a capacity of 45 litres but one time I put in 51 litres. Another time I did 600 ks but only managed to get 35 litres in and that's with the fuel tank so full it was starting to spill out.

What going on here?

[Guest001]

Dodgy pumps by the look of it

[sports racer]

Costco pumps.

Been using them 3 times a week for over a year and never had any issues with any other car.

[sports racer]

Figured it out.

The next tank of petrol only took me 430 ks so there must have been an air bubble, that's why it only took 35 litres.

Fuel economy seems to be around 7.4 litres per 100 k's with best being 7.1

[sports racer]

A few times when putting petrol in I can't completely fill up the fuel tank. Sometimes if I wait a minute there is a sound like someone sighing and then I can squeeze in an extra 10 litres. Yesterday no matter how long I waited it only took 35 litres and I know the tank was almost empty and should have taken 45 litres. Rocking the car didn't help either but that's because the suspension is pretty stiff and it doesn't move much.

A full tank is good for just over 600 ks. When it doesn't fill up properly it gets 450 ks and I'm back at the servo early.

Is there an easy fix to getting the trapped air out of the tank?

[Bora Sport]

If you look inside the filler pipe you should see a black plastic button on the right hand side. If you fill right to the top and then press that button it seems to vent the tank. You will hear the air going in. I can usually get another litre or so in after "burping it" and I can sometimes do this 3 times or more. My Polo GTI is the same. I have also found that if the driveway of the service station slopes towards the filling side you often have that short filling problem. If the driveway falls the other way, ie the passenger side of the car is lower than the drivers side I don't have any problems with the short fill.

[sports racer]

Thanks for that. I really need to look at modifying the tank so it takes more petrol. Filling up every 3 days is annoying especially when the MK2 Golf would go 4 days between fills with it's 55 litre tank.

[sports racer]

Managed to squeeze in 53 litres yesterday which isn't bad for a 45 litre petrol tank.

Couldn't find any button so filled the tank slowly.

[karmen]

happened to me and Caltex send me $50 voucher as the calibration of the pump@ servo was out!!!

[sports racer]

Wish that was the case but whenever it takes only 35 litres I only get around 450 k's out of the next tank so I know there's still air trapped in the tank.

On a positive note the central locking started working the other day. I was going to take a look at it this weekend but now I don't have to.

I love it when cars fix themselves.

[Bora Sport]

This is the venting button that i was talking about.

[sports racer]

Found it, thanks for the photos.

[karmen]

kiss it more often and it will sigh more
gotta check my Cordy and Golf for the MaGiC button lol

[Bora Sport]

My Polo GTI has one but I cant find one on my Golf R.

[sports racer]

On the Cupra the venting button sticks out so far the petrol pump nozzle has to push it out of the way when I fill up with petrol. I figure that's how it's supposed to work but last night it stopped filling up after the usual 35 litres so I pushed the button as far in as I could and I heard the air coming out.

Looks like I'll have to hit it with WD40 or take it off and give it a good clean.