Blow into the fuel return line (or use shop air). If you don't hear a gurgling in the gas tank, you may have a faulty check valve in the tank which is clogging the return fuel line.

Odd that it won't start/run on starting fluid, though. Almost sounds like it's spark related. Maybe you have a bad ignition switch...

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A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.