Im having some issues with my gas gauge? yellow light on and it takes 40L to fill up. I think the thing has a 73 l tank? it seems to be getting worse with the gauge dropping fast but only ever takes between 40 and 50 L??
could it have 23 odd L in reserve?
I seldom worry and just gas it go play (and pay) but curious if other vantage owners have similar readings

 

Two things:

1) The ground for the sending unit needs to be cleaned up to restore its contact and ability to ground. Hopefully it's this.

2) Your sending unit is going bad and needs to be replaced. Hopefully it isn't this.

Either way, the fuel delivery to your engine is fine, the problem is that the signal going to your gauge is bad. It says you have less gas than you actually do. This happened with me a couple months ago - everything was fine then all of a sudden my fuel gauge said I went through a full tank of gas in 30 mins of normal driving. Wasn't the case, of course, but it sure scared the crap out of me!

 

Thanks Telum01, can you stear me to this ground connection? I also have the factory manual but its quite vague and assumes the reader has had official training, so some guidance here will be appreciated possibly a pic will be of great value

 

Haha a pic!!??...I wish I had pics and I'm trained!! Aston has very little info, a pic is part of that little info not provided.

It's not to hard to access the sender unit in the tank, I've never had the ground connection turn go bad but anything is always possible. Being I'm not sure where the ground is with out looking at the diagram, it's fast to access the sender and check the resistance to ground at the sender, at the same time you can check the sender units potentiometer grid or damage and see what's going on when the light is requested on in dash

If you have a coupe, access is in boot, if you have a Volante, access is in the tonneau area

 

From what I saw oh PH, the ground is attached to the rear subframe. I poked my head under the car and nothing jumped out at me so I'm not entirely sure where it's at. I've honestly just put the problem aside for now - I've got too many projects I'm trying to knock out and a faulty fuel gauge isn't going to stop me from driving the car so long as I remember to keep gas in it.

As for diagnostics, Irish is always the authority

 

I would bet on the float being cracked so the float now has gas inside it and its sinking instead of floating so the reading on your gauge is less than it actually is .

 

valuable point, thanks for that
Irish in the coup, what carpets do i need to strip out to get to it?

 

The float is some kind of foam, cracking will not fill it with fuel, but if a piece comes off its possible not to prevent it from staying on top of the fuel...anything is possible.

The carpeted large slanted area in the boot has the fuel access plate underneath. Memory serves me, the metal plate is 2way taped on the body, then there is the pressure plate bolts to the tank with a oring sandwiched, make sure to put this oring back correctly or a evap leak will occur

And be careful of fuel, especially if tank is full, it's nasty to your skin..

 

This is how it was on mine. I'd highly recommend getting a new seal for the access port, mine ripped apart pretty easily when I removed the access port cover.

 

If its a foam float then a piece coming off wouldn't matter . If the foam became saturated with fuel and became heavier then that's the same condition as a cracked ball type float .