S70 Fuel Tank Pressurizing when trying to Refuel

jlrsn · Post by **jlrsn** » 12 Nov 2009, 15:23

My wife’s 1998 Volvo S70 has been almost impossible to refuel. I checked it and the fuel tank appears to pressurize after a gallon and will kick off the automatic fuel nozzle. When you slightly remove the fueling nozzle you can hear the pressure escaping. It takes a long time to put in even a quarter tank before we give up. I haven't had a chance to fully diagnose this yet but this problem just started when the S70 passed 100K miles about 4 months ago. Any suggestions?

Post by **MadeInJapan** » 12 Nov 2009, 16:09

There is a line leading to the charcoal canister...sounds like it is clogged up.

jlrsn · Post by **jlrsn** » 12 Nov 2009, 22:51

Thanks MadeInJapan,
That is exactly what I told my wife that I thought it could be but I haven't even had a chance to check it yet. From my past experiences with the charcoal canisters I usually found that the canister itself would be fully clogged. I've never experienced the line itself clogged. I'll try and get to it ASAP.
Thanks again,
Jim

Post by **polskamafia mjl** » 13 Nov 2009, 01:24

Hmm...I might have a similar problem. Can you shed a little more light about the canister and the line going to it? What does it do first of all, and second where should I look to find the line? the canister itself is towards the front of the engine bay on the driver side I think, right?

jlrsn · Post by **jlrsn** » 13 Nov 2009, 09:11

OVLOV,
That’s the first place I looked but per my understanding now the Charcoal Cannister of the S70 is in the rear just forward of the fuel tank. I haven't had a chance to check it out yet. I found a YouTube video of the Charcoal Cannister location at:

Good luck,
Jim

Post by **Brucebo** » 13 Nov 2009, 11:08

polskamafia mjl wrote:Hmm...I might have a similar problem. Can you shed a little more light about the canister and the line going to it? What does it do first of all, and second where should I look to find the line? the canister itself is towards the front of the engine bay on the driver side I think, right?

Your problem could also be a stuck closed cannister shutoff valve. Pressure in the fuel tank is vented to the outside through the charcoal cannister (unless the shutoff valve is closed). The cannister adsorbs fuel vapors while letting the air through. During a purge cycle fresh air is pulled, through the open shutoff valve, through the cannister into the intake manifold, taking all the adsorbed fuel with it and refreshing the cannister. See the following local link:

https://www.matthewsvolvosite.com/forums ... &sk=t&sd=a

Post by **polskamafia mjl** » 13 Nov 2009, 12:39

Thanks a lot guys.

jlrsn · Post by **jlrsn** » 13 Nov 2009, 16:30

Brucebo or others,
The diagram shown in the referenced thread is for an 850 with a VIN Emission Code 8th Digit of 4. My wife’s Volvo is an 98 S70 with an Emission Code 8th Digit of “7", not “4". Do you know if the Emissions System has changed between an 850 to a S70 and if it has a similar Shut-0ff Valve can it be bypassed or will it create engine run problems and leave a Code?
Thanks for your help,
Jim

Post by **Brucebo** » 13 Nov 2009, 21:11

jlrsn wrote:Brucebo or others,
The diagram shown in the referenced thread is for an 850 with a VIN Emission Code 8th Digit of 4. My wife’s Volvo is an 98 S70 with an Emission Code 8th Digit of “7", not “4". Do you know if the Emissions System has changed between an 850 to a S70 and if it has a similar Shut-0ff Valve can it be bypassed or will it create engine run problems and leave a Code?
Thanks for your help,
Jim

I believe they're "conceptually" the same, but the locations, p/n and geometries are different. The purpose of the shutoff valve is to facilitate the EPA mandated EVAP (Evaporative Emissions) test, which tests that your fuel system has no vapor leaks. During this test the shutoff valve is closed and a small vacuum is pulled on the fuel tank by the purge valve. This vacuum is then monitored to see how fast it decays. If it decays too fast you fail the EVAP test and your MIL is lit. This will also happen if you leave the gas cap off or loose. If you remove the purge valve you will fail this test at some point during the drive cycles.

-Bruce

KEWROCK · Post by **KEWROCK** » 14 Dec 2009, 17:57

I have this same problem in my 99 V70. It takes fuel fine if the engine is running. But but when it's not running I have to let the fuel dribble in. I'm having an evap related engine light problem Too.