I bought an '01 S40 last week and have come across the same fuel tank capacity issue as several others I have seen posted here. Specs list the tank capacity as 15.9 gallons. I haven't driven it until the light comes on, but have driven it down to E twice. Both times it only took 10.5 gallons to fill. Both trips the fuel econ has been around 24 mpg with mixed driving. Any ideas, or is Volvo just playing it safe and leaving us all with 4 or 5 gallons to spare?

 

That is the question. Now, who will drive theirs until it quits to find out?

 

Theres got to be some type of reserve on the tank;as I recall, on the 2G S40 the fuel capacity is 14 or 15 gallons, and I have always put in 12-13 gallons everytime my car goes well beyond "0 miles left", and once I was able to put in almost 16 gallons!

 

I think Volvo is definitely playing it safe from what I've been reading. On aside note, Prius owners have a similar problem. Depending on the time of day, temperature outside, humidity level, the moon's phase (call it the 'x factor') owners can't get a complete fill at the pump. Seems Toyota put a bladder inside the fuel tank and gas vapors hinder fillups. So the car's computer will tell them they've used, say, 10.5 gallons and they might only be able to pump 8.5-9.0. With the S40s it might be an extreme case where there is a very generous reserve capacity as well as vapors making it difficult to pump it full(?).

 

I have a 2000 S40, same thing. The gas light comes on and needle is below empty at about 250 - 300 miles. I fill up at 350 miles, putting about 14 gallons in. I followed my wife to Ohio from PA on Thanksgiving, I figured it was a good time to try it. I put in 15.35 gallons of gas. I think Volvo just really wants you to be safe, imagine that from Volvo.

 

15.764 gal just the other day...to the pump. luckily I was planning on getting gas... but only after I went to the market. On the way I had to whip it in real quick to the pumps as I could feel it dying on me.

now I know how much MY Gas tank holds.

Have a good one all.

sUSAn

 

Does anyone know how the fuel sender operates? Is it like other cars and uses resistance to operate the gauge? (like the old 0-90 ohm senders) I ask because if we can find out how the sender operates then we can also find a way to mod it so it reads correctly.

EDIT: to add, it may just be as simple as bending the float.

 

I was on another volvo forum site and this is what they replied to me with.

"Common problem with earlier S40. It has been solved on later 2003-2004 with newer part from Volvo. Your tank capacity is 15.9 gallons."

They also suggested that the needle might needed to be calibrated. As far as the tank, it is an issue with the Fuel Pressure Regulator. The part isnt too terribly expensive if you order it.
http://s40concepts.net/forum/index.p...d002f0ebbbba09

 

That was a very interesting read. The fix was indeed bending the float arm.

I'm not sure what you mean by "As far as the tank, it is an issue with the Fuel Pressure Regulator." On the S40, the FPR has caused many a hard start problem. Just not sure which issue you are referring to is all.