Fuel Capacity V40

jefe · Post by **jefe** » 25 Jan 2011, 09:41

Hey all. So I know this has been brought up a 1,000 times but my wifes V40 is having the same issue where the manual states it holds 16 gallons of fuel....but the gauge says it's empty and the light is on and when she re fills the tank, it's only putting in about 9 gallons....leaving us to believe there is still 6 gallons or so left in the tank.

In the repair database, there is the 'Service Manuals & Fuel Capacity' thread that I thought was a good read and informative.....I was just wondering if anyone out there also had success following the advice in that thread.....whether it was done by yourself or if you took the advice to a Volvo dealer and let them sort it out.

Thanks for any feedback on the topic. - jefe

jefe · Post by **jefe** » 30 Jan 2011, 10:31

anyone?

Post by **jimmy57** » 30 Jan 2011, 11:37

The tank is of a shape that doesn't lend itself to being accurately measured by the electrical level sensor. There is an area of something like 4 gallons that is above the sensor's reach. The instrument cluster will assume you filled it ALL THE WAY if the sender goes from a bit less than maximum sensor reading to maximum sensor reading when key is off and then back on it will move needle to full scale and assume the tank is full. Then the fuel gauge is moved by use of fuel consumption info from engine computer. When the fuel level sensor begins to drop from maximum signal then the gauge is re-calculated and needle is moved. This will result in the top 1/4 scale of gauge can last 15 miles or 90 miles or maybe even more depending on how full the tank was actually filled and the MPG after fueling the tank until sensor in tank begins to change signal. I had a 2000 V40 and if I parked with fuel filler on the low side It would click off and if I stopped at the first click then my usable fuel was low but I would notice the gauge drop a significant amount not too far down the road.
As with all carmakers, the amount in manual and how much you can use before the gauge shows empty is not the same quantity. You would have to run out fuel to get anywhere close to the capacity as it is dry capacity, not usable capacity before gauge gets near empty as indicated. If what I listed doesn't seem to fit with the experience with your car then you can go to dealer and they can adjust the gauge system with their computer tools.

jefe · Post by **jefe** » 30 Jan 2011, 23:46

Don't take this the wrong way as I'm not trying to be rude. I know you are trying to help but none of that really made any sense to me.

My wife says her tank goes from full to empty pretty fast, in about 250 miles. On empty, she fills up but the fuel shuts off after only putting in about 9 gallons of gas even though the manual states it is a 16 gallon tank. I can understand the gauge reading empty with still 1 or 2 gallons left in the tank, but it seems like a stretch to be sitting on empty with 6 or 7 gallons left.

One guy on here claims that he ran his to empty and put over 450 miles on it verifying that the manual is true about the gas tank being 16 gallons. This same guy also documented a fix to get the fuel gauge a more accurate reading and I was curious if anyone else on here has tried that fix and to what success they had.

Did you ever take yours to the dealer to have them adjust it?

Post by **jimmy57** » 31 Jan 2011, 05:50

From experience, the dealer fix of using VIDA to do an update of fuel gauge and possibly adjust the gauge range is only effective at being a fix and making you happy if you eliminate any operator conditions that might aggravate the condition.
If you are not getting tank truly full and you fuel again when low fuel light illuminates you could be cutting the range when nothing is wrong with gauge.

dolphsett · Post by **dolphsett** » 06 Feb 2011, 08:07

I own an '02 S40, and of the many quirky things about the car, this one is the most puzzling. My tank is exactly the same -- reads empty around 250 miles, then only takes 9 gallons to fill it. I've been using my tripometer to gauge fuel consumption. That doesn't prove too much of a hassle, but it throws off the computerized info centre feature -- no way of knowing if the MPG and the miles remaining to empty are accurate.

I've read the post you referred to regarding a mechanical fix, but unfortunately, I'm no mechanic and would never venture the repair myself. What seems odd to me is that Volvo never fixed the problem -- it's not like a fuel gauge is cutting edge new technology.

Someday I'll get the nerve to test the amount of gas that's actually in the tank by running it to -- or close to -- empty. But in the meantime, I'll just keep "filling up" around 250 miles.

jefe · Post by **jefe** » 06 Feb 2011, 20:06

I know what you mean. It seems very odd that with what seems like a common problem, Volvo never fixed the issue or had a recall about it.

My wife is currently running the volvo to empty cause it bugs her too much filling up at 250 miles all the time. At least this way she will know how many miles she can go before she really has to fill up.

Normally, just like you, the low fuel light is on around 250 miles or sooner and she has been filling up. Right now, she is over 350 miles on her trip meter even though the light has been on for over 100 miles.

I'll post again and let you know how far she makes it on this tank and how many gallons it took her to fill up. I'd wager it would be similar for you. Might be good info to share on here.

Maybe down the road, I'll try that fix from that other post but right now it's not top priority.

Thanks for posting!

jefe · Post by **jefe** » 08 Feb 2011, 09:41

She ended up going about 420 miles before she ran out of gas. It took 15.3 gallons when she filled up.....giving her about a 27mpg average.

Hope that helps someone out there get a little more mileage out of their tanks.

babelfish · Post by **babelfish** » 08 Feb 2011, 15:31

My father's S40 is identical -- takes 9-10 gallons when the gauge is on empty.

This has been a Volvo problem for a very long time, though -- I had the same issue on my '85 240 wagon and on my '91 740 sedan, though it was not so pronounced in either case. The 740 also had a weird issue where the gauge would diminish at an accelerated rate once past half a tank. It would get down to 1/2 pretty steadily, then after 20 miles would be below 1/4. It was pretty crazy. And it still wasn't even close to accurate -- 16g tank would read empty after 12g.

dolphsett · Post by **dolphsett** » 21 Mar 2011, 17:34

Thanks for the info Jefe. I'm goin' bold and see if I can get it to 400 miles this time. My info centre mpg says I'm getting 26.8, which I think is correct. It will be nice driving past the gas station for a few more days. Wish me luck.