Fuel tank sizes?
 

So both of my cars are imports so I don't really know any of the history behind them. My s4's a savanna gt limited which I think is the model below the ifini as it came with climate control etc. And my s5 I don't really know what model it was. Was filling up the s4 the other day and noticed it's got a 45 or 50L fuel tank in it, while the s4's got a 70 - 75L fuel tank in it.

Were these an option or has my s5 got an aftermarket tank in it?

S4 tanks were around the 16.4 GALLON area and the S5's were aroung 18 gallons. Something to keep in mind when swapping senders, straps... whatever. Dunno what a litre is.... litre cola maybe ;)

Give him a break, he is from Australia.

Seriously, 63L and 70L (S4 and S5)

Screw your gallons, thats really odd the one in the s4 must be smaller. Because theres no way its more then 45L ive had it right on empty and it took 42L or something.

Do the gas stations in Australia use those anti-smog vapor recovery nozzles like they do here in the USA? If so, I've found that in the warmer months these pumps like to shut themselves off prematurely when filling up my '89T2. I assume the anti-smog nozzle function interferes with the tank's ability to properly vent itself, so when it's hot outside, you get a big pocket of air trapped in there that prevents the tank from filling completely. Fix for me is to just remove the nozzle partially, allowing some air to escape, then re-insert and start filling again. You might have to do this several times to completely fill the tank -- on really hot days, I've added another 3~5 gallons after the initial pump shutoff this way.

That thing is a PITA regardless of the car. My truck for example, after it shuts off I can ALWAYS get an extra 1.5-2gals in.

Might be a good idea to add this information to the FAQ/archives, in case it comes up again in the future.

European cars, sizes were not different only by Series, but by model (turbo or NA)

S4 NA = 63L
S4 TII = 70L
S5 TII = 70L
S5 NA = not offered on EUDM

Just to bump this, drove the car till it was close to running out of fuel the other day, as it was the day before pay day and I spent all my cash on other goodies. Think my gauge is out of cal, as I was very unsure if I would make it home. It went down to where I should be out of fuel and the fuel light was still coming on and off not staying on solid. Got it to the servo the next morning and it drank 58L of fuel. When I had filled it up the week before from a fly shit above empty it took 40L.

When my S4 was stock, the gauge would drop to 1/2 in 100 miles, then it would take 200 to 250 miles to get to empty. From what I remember, when the light started coming on I had roughly 3 gallons left.

There is a possibilty that your sender is a little off, the gauge is a little off, corrosion on one of a dozen terminals, etc etc. The fuel gauge is an ohmmeter.... any resistance anywhere is going to affect the readings.

a common issue on the 2nd generation sending units is for the sending unit wires to fray near the bottom of the tank, throwing off their calibration at lower fuel levels.

i've been noticing it alot more lately as the cars are getting older.

I have no idea what you are talking about...

If it was indeed fraying, there would still be electrical contact.
When the wire completely broke, it would obviously lose signal.
Even if you had one wire still intact, the voltage is low enough that one strand of wire would still provide an adequate signal.

I just changed my fuel level sender in my 1987 turbo and saw no evidence of "frayed" wiring.
It was the potentiometer resistance sweep (common problem for any type of (non-sealed?) potentiometer) to degrade this way.


-ted

Do remember they idiot proofed gas tanks. They have a "Reserve" so that people running them to Empty did not run out of gas right at that moment. I know my Taco has a reserve to get another 100+ miles to get some gas.

On my 74 BMW 2002 Empty was Empty I am not sure as to what year they enacted this.

I had the exact same problem on my sender when I was using the stock dash.

When I changed out the dash and built my own using all aftermkt gauges I first tried the autometer generic replacement sender = SHIT
Then I tried the marine Tempo sender = less shit, but still shit.
Then I bought a new Mazda sender and a programable autometer gauge = awesome.
Then I built my own tank and went with a WEMA and the same Autometer programable sender = awesomeness

If you need to replace the sender, which I suspect is highly likely, as Ted said, non sealed units as they are, you can actually see corrosion on the sweep giving inaccurate signals, I have yet to find a better sender than the Mazda units. Aftermkt wise, WEMA is the way to go.

:rofl: I've noticed that with alot of newer cars as well, take my Jeep. When the light goes on there's about 100 miles left if you're on the highway at a reasonable speed. Cold winter mornings letting the truck warm up and siting in traffic, 50 miles. I know this becuase I put 5 gal in my mounted jerry and drove the thing empty, twice :rofl: Then I drove a few miles to the gas station and put 15.3 gal into a 22 gallon tank. Stupid vapor reserve things