Gas smell in '73 Euro 911

I recently purchased a 1973 Euro 911 and discovered a gas smell in the interior. I have and replaced the clear vent hoses as well as removed and checked the "black box" behind the dash for leaks-none- (as it is a Euro model the box is empty and has no charcoal in it. I seem to be getting the odor more on acceleration even when the tank is less than 1/4 filled. The car has MFI and I have had the pump rebuilt and replaced the injectors. The CO is dead on at 4% and the car runs strong. Does anyone on this board have experience with this problem or any suggestion as to where to look next for the source of the odor? My wife will not ride in the car until it is fixed.

Todd

Todd,
Your wife isn't the first and won't be the last..
... girlfriend in my case.

I was struggling with the same problem for a long time. If all the other obvious things have been checked (gas cap gasket, plastic and rubber hose connections, etc,) I would definitely go back to the BLACK BOX (which is one of two expansion-boxes in the system and did not contain charcoal ... the charcoal canister is down by the left battery in U.S. cars) Not only check the connections of the hoses on the little plastic bungs, but the integrity of the box itself. They tend to separate at the seem and or crack at the very top. It doesn't take much with the box that close to get a whiff. The box is thermoplastic and almost nothing sticks to it, however you can 'weld' it with a simple soldering iron. To test it, plug one of the bungs and blow in the other and see if the box expands.... OR just go out and buy a new one at the dealer, they kept that box through the SC's.

Good luck Todd,
Chuck

alternatively....try eating fewer beans....

Tru Brit was funny..LOL here, But Chuck? Good advice! Can't add a thing.

If you smell it just as strongly with a 1/4 tank as with a full one, I would not suspect the venting system as much.

Check all the gas lines leading from the tank back to the engine, too (feed and return). They run right thru the center tunnel, and if they are weeping from a small crack, you will smell gas in the interior without seeing a visible, wet leak, as the gas goes to vapor quickly.

TT

have you checked the gasket on the fuel guage float at the tank? If it aint the box or the vent lines I would look at this gasket, could be the cure.