81 240 fuel problem

My 81 all of a sudden has an intermittent gas smell under the hood,
and the fuel pump is staying on all the time at idle instead of
pulsing on and off.

As this is my first FI car, anybody have any ideas where to look
first? I've traced the lines from the underhood fuel filter and the
one off the high pressure pump and there's nothing obvious...

 

The fuel pump should be on all the time the engine is running (or
cranking).

Assuming you have no external liquid leaks, start by looking at the
charcoal canister, which is mounted under the left front fender. Check
the hoses from there to intake manifold, and if you can see any liquid
there, you'll probably need a new canister. Also injectors can drip
with the engine off, and the smell makes its way out the air filter,
although this is usually accompanied by hard starting when hot.

I know you say that the smell is coming from under the hood, but a
common place for failure is the vent pipe on the top of the fuel sender
in the gas tank. There's an inspection port in the trunk that can be
removed for a quick look.