Box 2003 S. Fuel tank won't fill. Read other posts. New gas cap, changed pressure relief valve on filler neck. There is a 'click' with the top flap pushed in. E6 fuze ok. Checked and replaced. With tube from relief valve to carbon canister disattached the tank fills. Reattach it and won't fill again. Took canister out and looked ok. Not falling apart, no pieces floating around. Took to dealer and they poked around and didn't find anything but did say he wired up the wires that are mentioned in TSB #13 and he said it filled up. I tried it four times at different locations and times and failed every time. Tried to find the tank relief valve but couldn't find it. It is sometimes hesitating, like a miss, but usually runs fine. Any comments? Thank you in advance. jp

 

What does the gauge show when you try to fill it up?

 

The gage is accurate. I've been waiting until at least a half of a tank left to start my experimenting. I found out the hard way that the tank has to be filled to reset itself if power has been interrupted. But gage is ok.

 

Today coming home the car was hesitating some times during acceleration and one time died while waiting at a red light. Is this an indication of the carbon canister going bad, too?

 

While the charcoal canister can fail at any time most often they do not go bad. However, if you make it a habit of overfilling the fuel tank this can put raw gas in the canister and they don't like this.

Rather than a bad canister it reads more like the symptoms of unsufficient fuel supply or pressure though an intake leak which can even include a failing AOS can also be an explanation.

 

We have service station attendants here and they go to great lengths to make the delivery and even number so click, click away they go. The canister seemed ok since it passed air so I'll check the AOS. Thanks

 

Update: Both the fans failed on the way home. That is why the a/c quit and engine temp started to climb. Fuel tank has been checked for over a month. Every thing I've read here has been tried to no avail. Porsche has been contacted by the dealer and those suggestions, that I don't know, have been followed to no avail. The dealer is taking videos of something and sending that to Porsche today. May have a response tomorrow. I have changed the fuel filler cap, the relief valve on the filler tube in right wheel well. Checked air flow through the tubes I could get at including the charcoal canister. What did work for filling the tank was disconnect the relief valve from the charcoal canister and go fill up. Worked but I got a Check Eng light. And that reset and switched the relief valves and hooked up the tubing again. No go on the fuel tank. I have not tried the previous but told the dealer investigating the sitch of that event. He has not told me if he reattempted it cuz he's doing the Porsche suggestions now. We'll see.

 

Thanks for the update.

Has the tank be opened up -- the fuel pump has to be removed -- to inspect the inside of the tank. Maybe something (hardware or?) has come loose and is blocking the fill tube?

That's all I got.

Well, there could be a problem with fuel vent system but my 2nd hand info is this is checked out pretty thoroughly as part of the readiness monitor testing the DME goes through after engine start and as the engine runs.

One would think that if there was a problem in this area at least a pending code would be well, pending.

I would hope the Porsche tech would use whatever is offered in the way of support by the Porsche diagnostic computer to ensure this system works as it is supposed to.

Have you tried turning the nozzle upside down and hold it securely against the tube opening? Nozzles with the vapor recovery system can be really sensitive. I found early on some nozzles were very sensitive and filling the tank was hard to do because the nozzle shut off prematurely.

While I don't like to overfill the tank -- to avoid getting raw gas into the charcoal canister -- I like to fill the tank until the nozzle shuts off because the tank is full. If the nozzle shuts off sooner that's not good in my opinion.

Turning the nozzle upside down works about 9 times out of 10. That 10th time the nozzle can still shut off prematurely and extra effort is required to get the tank to its normal full level.

 

Macster
I tried the upside down trick. It was ok but then I did take a fuel bath. There is no vapor recovery system on these pumps here. But they all have attendants and they fill up to the top to even out the cents. I've told them for ever not to fill to the top. Language barrier plus the pressure to round off to the cent. But canister had airflow through it nor did it slosh when I took it out to inspect. I'm hoping with the video sent to Porsche yesterday I might get the car back today. The top has been taken off the top of the gas tank and all inspected ok. The 'tie off' mod was done plus taking out the flapper valve half way down the filler tube. Exasperating.