Hi, I bought my Audi S5 Cabriolet last week and for some reason it doesn’t fill to a full tank does anyone know why this could be.

Thanks Gaz

Do you really mean the tank can not be filled, or is the problem actually that the fuel guage does not show full?

The pump stops as if it's full but the gauge doesn't show full. When I start filling it up it is temperamental too. 

Hello Gary,

So the filler pump nozzle cuts out (consistently?) when trying to put fuel into the tank - correct? 
Does it do this even when you try to trickle the fuel in by barely opening the nozzle lever? 
If these are the issues you are getting, it could be a faulty/collapsed beather pipe, or perhaps the filler flap isn’t opening sufficiently when you insert the nozzle.

Kind regards,

Gareth. 

 

Sounds like the problem I had with my Mondeo.

You could start filling up but the pump would constantly click off. Eventually got so bad that fuel would be blown out the fill pipe and over me.

That was due to the charcoal canister being blocked, the fuel tank couldn't empty the vapours through the canister so it was pressurising when filling up.

5 hours ago, Gaz1977 said:

The pump stops as if it's full but the gauge doesn't show full. When I start filling it up it is temperamental too. 

You aren't giving us much detail. Does fuel blow back through the fiiler pipe? Can you hear the fuel level rising up the filler pipe? In what way is filling temperamental?

The fuel doesn't blow back out.

It keeps clicking off.

I can’t point you towards any other possibilities other than a blocked filler breather. I would be checking this before delving into other possibilities. 
Does it behave any differently if you just trickle the fuel in (already asked but no reply), or indeed if you alter the angle the fuel nozzle? 

This is like trying to get blood from a stone. Unless you give us something more descriptive we shall get nowhere, so let me ask some very specific questions.

[1] Just before the pump clicks off can you hear any difference in the sound of splashing as the fuel rises up the filler pipe?

[2] What does the fuel guage show when the pump clicks off?

[3] When the pump clicks off can how much more fuel, if any, can you get into the tank if you trickle it in?

[4] In what way is filling temperamental?

Details matter as we have not established yet whether you have a faulty fuel guage or a restriction in the filler pipe or a blocked breather pipe.

I apologise for not being on here much. The pump cuts out constantly yes whilst trying to fill it. I have to trickle it in. Just wondered if there was a known problem with them. 

 

1, It clicks off immediately I start filling the tank as if its already full.

2, It clicks off right at the start I have to trickle it in.

3, if I stop when it first clicks off I would put below the minimum in.

4, I can't just put the nozzle in and pull the lever until it is full.

You still don’t tell us whether it is possible to ‘trickle’ fuel in by barely opening the nozzle lever -or not. 
You don’t tell us whether you have inspected the fuel filler breather pipe as suggested - or not! 

Gary some us know when you visit the forum so your excuse will not wash. That, and your lack of answers to direct questions, means I shall no longer respond to this topic.