348: huge pressure in tank, is this normal?

Hello people..

Have my '93 348TB just one week now so there might be more small items to ask in the future. Don't flame me..

When I unscrew the fuel cap the tank everytime makes a huge blow of the pressure inside. After a ride of course...Is this normal or what could be stuck ?

By the way, I had also yesterday the passenger-window-non-open thingy.
As I found out after searching a very common matter.
Of course it was the bloody connector... works ok again now.

 

When the cap is opened the car passes gas. It is completely normal.

 

The passenger window of the 348 was slow when I got the car about two months ago. I had it fixed at Tim Stanford's. The basic cause is the way the electrical wiring was done for the doors. The wiring that goes between the door and the body of the car is a large plug in with about twelve wires. Instead of the wires going continuous through the body, they are plugged in at the connection at the body. This causes the wire to make a pretty severe bend every tim eyou open the door (and the doors have to be opened pretty wide to get into a 348). After several years of being bent, the individual copper strands break leaving fewer and fewer strands to carry the current to the motor. They replace a section of the wire including the connection where these wires bend and (internally) break. If you try the passenger door switch it will usually work better for the passenger window. That is because the passenger door is used less and less of the strands are broken. Also, corroded or faulty switches are sometimes the culprit. They replaced six wires in my driver's door and now the passenger window works well. If your window is hanging up while it is raising, you can adjust the position of the track by shimming the window mechanism. Take off the door loever from the outside to work on the window tracks. Hope this helps. I also had some work done on the electrical circuit for the A/C blower to reduce heat buildup in the wiring that is a common problem with 348's.
BT

 

Yes, air does come out of the gas tank whenever it is opened during a fuel refill.

I myself have always wondered why. Can anyone explain?

 

Henkie: I had the exact symptoms, huge blow, nothing like I'd ever seen before on any car, so much pressure that I thought it might blow off some important lines, etc. Traced it to the "upside down" valve. It's a valve about half the size of your fist located with the carbon regen filter on the left side of the engine bay. Basically it's a flapper valve that's supposed to vent the positive pressure on the fuel tank in case of a rollover. I suspect they fail to the point that they stick and allow too much pressure to build up when you are right side up. I routed around it. No more pressure. It's another "emmissions" gimmick that does nothing good. If you didn't pressurize the tank, you wouldn't need to relieve it in a rollover.

 

Ok, so I'm not the only one. It must be quite normal then.
I'll accept it and won't hang with my marlboro 10 cm's above the fuel cap when I open it.

(ah, well... I don't smoke)

 

normal - I noticed it would get reaally bad if you topped the tank off also...