S40 Fuel Tank / Gauge questions
 

Hello all,

I have a 2001 S40 1.9T. I absolutely love the car. However, I am puzzled by one thing. All the literature says the gas tank holds 16 gallons of gas. But, when the computer says I've got 30 miles to empty, and the fuel gauge is bottoming out, if I fill the car up I can only squeeze in about 10.5 gallons. I am really puzzled by this. Do I really have more gas in the tank that the car just doesn't read is there, or do I have a weird 11 gallon tank?

Thanks in advance.
Mike

RE: S40 Fuel Tank / Gauge questions
 

I think the computer is supposed to say there is less fuel than there really is, hoping people wont run out of gas.

RE: S40 Fuel Tank / Gauge questions
 

There is also software from the dealer to recalibrate the guage to make sure it is accurate.

RE: S40 Fuel Tank / Gauge questions
 

I also have a 2001 volvo s40 and my only problem is the gas gauge. It reads empty after my car consumes 10 gallons of gas. I went to the dealer and had the software upgrade done and this cost me 150.00 usd. But it is still doing the same thing, can someone help me with this. Chris

RE: S40 Fuel Tank / Gauge questions
 

Sounds like a bad sending unit.

RE: S40 Fuel Tank / Gauge questions
 

So if it is the sending unit how do i change this?? I understand on some older models you can get to it through the trunk. This is a 2001 s40. Wish I had not paid for the software upgrade. Chris

RE: S40 Fuel Tank / Gauge questions
 

I haven't had to do one yet. It is not a common problem. I will check tomorrow and see if I can find out info for you.

RE: S40 Fuel Tank / Gauge questions
 

Thanks.:D

RE: S40 Fuel Tank / Gauge questions
 

I also have a 2001 S40 that I bought a month ago and I was puzzle about the tank capacity. I am hardly getting 200 miles per full tank and I am not riding it hard. I have another Volvo a 1990 740 turbo and I get 300 miles per tank and the motor is bigger (2.3). Could it be that is not reading correctly?, when I fill up the S40 I have to push in $17.00 of gas, while the 740 takes easy $ 24.00.
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RE: S40 Fuel Tank / Gauge questions
 

Tech you find out anything for me yet???? Chris

RE: S40 Fuel Tank / Gauge questions
 

Haven't been able to find anything yet. I will call my buddy tomorrow.

RE: S40 Fuel Tank / Gauge questions
 

Hi Chris.

Might be worth depressurizing the fuel system first (remove fuse #17 - fuel pump I believe - but do check!) then run the engine until she stalls. Once 2 attempted re-starts have failed, switch off & replace the fuse.

Make sure you know the radio code, disconnect the battery, fold down the rear seats & then loosen the front edge of the carpet in the trunk.

There is a load support under the carpet which needs to come out so that you can see the sender unit access panel in the trunk floor. Remove its securing screws & the access panel itself, then the cage underneath.

Once the fuel lines (rags at the ready!) & wiring connector are removed, you'll need wide-opening grips or similar to carefully remove the plastic retaining nut. It is recommended to refit the plastic nut immediately the unit is out, to stop the pipe stub swelling up.

Personally, as petrol is involved, I'd fit a new seal but if the old one looks OK then re-fitting is your own choice.

Hope this helps.

BB
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RE: S40 Fuel Tank / Gauge questions
 

Re your message Chris, the reason I suggested de-pressurizing the fuel system first is that if you pull the fuel lines off of the sender unit without depressurising the system, petrol will spray over the top of the sender unit & into the trunk. Unsafe & the smell of petrol will linger for a very long time.

There are other ways of de-pressurising, but the one I've mentioned doesn't involve you releasing petrol into the atmosphere, therefore i.m.o. it is the safest, especially when DIY. Just remove the fuse for the fuel pump, run the engine 'til it stalls & once the engine has refused to re-start two attempts in a row, the system is definitely depressurised.

Tech suggested on 14/1 that the sender unit could be bad. If you feel it could be bad, then to remove the sender unit you can follow the guidance I've given. If the unit looks OK visually, then maybe get an auto electrician to check it out (Tech - am I right in thinking that measuring resistances would be the way?). Forgot to mention that the seal should be lightly moistened with petroleum jelly before fitting.

Please do remember that in order to stop us mere mortals running the tanks dry, manufacturers do tend to err on the side of caution with fuel gauge readings & low fuel warning lights. Not such a bad thing when you consider how inconvenient & potentially dangerous running out of fuel can be, how infrequently some drivers check their gauges & warning lights, plus the fact that running low on fuel risks crud from the bottom of the fuel tank finding its way into the fuel pipe & filter. When the fuel warning light comes on, there will normally be at least 2 gallons of fuel left in the tank of most cars, sometimes more.

If you're familiar with BBC's Top Gear motoring programme & presenter Jeremy Clarkson, he did an experiment involving a big Audi diesel to see how far he could drive on 1 tank of fuel. It was a while back, but from memory he drove well over 100 miles with the gauge reading nil & the low fuel warning light flashing.

Best of British!

BB
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RE: S40 Fuel Tank / Gauge questions
 

Will try and get to this next month too busy right now, but will let you know what happened. Thanks for your help!!!

RE: S40 Fuel Tank / Gauge questions
 

I just had to replace one Yesterday. Move the front seats all the way foward. Then fold the rear bottoms up. Then lift the carpet. You will see a black cover with 4 Phillips screws holding it to the floor. Remove the 4 screws and remove cover. You will see the sending unit assembly. After you have releived the pressure and removed the lines.You are supposed to use a special tool to loosen it. Well we don't have the tool I used a screwdriver and tapped it CAREFULLY. Once the ring is off if you are going to replace try to work pretty fast. Or reinstall the ring TEMP. Volvo had a warning in our computer that if you didn't do it the tank would swell and you will have a hard time getting the ring back on.

Hope this helps.

RE: S40 Fuel Tank / Gauge questions
 

Hi I have a similar problem with my 2000 s40. when i fill the tank to full gauge work ok but after run few miles ( about 10 miles) the gauge go down to about 3/4, sometimes to half, the gauge never work well, sometimes it seen to be working fine but not stay for a while, other ocasions when i start the car the gauge don't go up. Somebody tell me that it could be a electical problem but really i don't know what really is causing this.

bringing an old thread back to life-

have a 2001 s40 that maxes out at ~10.6 gallons of fuel after running on E for a while. was this problem resolved? any help would be very much appreciated.

The 2000-2004 S40's have about a 16 gallon tank. For some reason the gauge is calibrated from full to empty at about 10 gallons. I have read a thread on another forum where the poster removed the sending unit and bent the float arm so the gauge read more accurately. Mine has always acted this way.

Diesel gauge sticking
 

[Would this apply to an 2006 diesel?

QUOTE=tech;18946]I just had to replace one Yesterday. Move the front seats all the way foward. Then fold the rear bottoms up. Then lift the carpet. You will see a black cover with 4 Phillips screws holding it to the floor. Remove the 4 screws and remove cover. You will see the sending unit assembly. After you have releived the pressure and removed the lines.You are supposed to use a special tool to loosen it. Well we don't have the tool I used a screwdriver and tapped it CAREFULLY. Once the ring is off if you are going to replace try to work pretty fast. Or reinstall the ring TEMP. Volvo had a warning in our computer that if you didn't do it the tank would swell and you will have a hard time getting the ring back on.

Hope this helps.[/QUOTE]
I

"CapacityFuel tankOctane rating: Unleaded premium gasoline with an octane rating AKI of 91, or above. The minimum octane requirement is AKI 87 (RON 91).15.9 US gallons (60 liters)
Models with All Wheel Drive have a tank volume of 15 US gallons (57 liters).
Models with engine code 39 have a fuel tank capacity of 14.5 US gallons (55 liters). This code is the 6th and 7th digits from the left in your vehicle's VIN number.
See page 184 for the location of the VIN plate."
Having run my 2005 T5 AWD down to the warning light just the other day I can tell you it only took about 10.5 gallons to fill it. Apparently it's still true in 2006.