Check the fuel line from the steel pipe on the frame to the fuel distributor. They are shrink-fit material, and crack with age. If it's leaking (you will have to remove the air filter housing to check), cut it off and replace with standard high pressure fuel line and hose clamps, it's difficult (and expensive) to get a factory replacement for some reason.

Otherwise, check the vacuum lines for the evaporative control stuff. There are two small vac lines that go to the mainfold under the airflow meter, connected to a large hose and a valve. If the large hose is broken, fuel vapors will collect in the charcoal canister until it fills up, resulting in both fuel vapors leaking into the engine compartment via the broken line and overflow out the vent on the canister (down by the tank, I think).

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!