88 E28 Gas smell in trunk

[Aaron Lung <alung@xxxxxxxxx>]

I have an 88 528e (motronic 1.1).  Lately,
there's been a very strong gas smell in the
trunk.  Inside, there is an gas expansion tank with
3 rubber hoses leading out to the gas filler
and down presumably out to the gas tank and one
more metal pipe going out towards the engine.

I assume the odor is coming from this little
plastic box and/or hose connections.  

Has anyone had any problems with the purge valve
working properly or leaks in the expansion tank?
Isn't it supposed to be airtight?

Side note:  I've barely been able to pass
emissions on this car at idle in the past 2
tests over 4 years.  HC emissions are just
about at the limit.  Wouldn't a purge valve that's
stuck open also cause this?   Idle is a tad rougher
than silk with an occasional puff sounding like
a misfire, but the engine runs smoothly otherwise.  

I have most of the obvious done--new wires, cap, rotor, 
plugs, O2 sensor, air filter, and valve clearances
verified OK.

any ideas?

I think I remember someone posting a similar problem
a few months back.  I don't remember seeing the reply
if any.  Apologies if I missed it.

thanks
aaron

88 528, 67K miles

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