Hmmm...



It's possible the leak is so bad that flooding is preventing it from starting, though if it were that bad it seems like it would hydrolock.

Next time you drive it and put it to bed for the night, don't turn it off. Pull the fuel pump relay first and let it run itself out of gas (then turn it off). This will insure that it can't leak any fuel overnight. Or, just put a bunch of paper towels under the fuel supply line & slowly disconnect it and let the fuel drain out to relieve all pressure in the system.

Next morning, pop the relay back in (if you took it out), prime it a couple of times and then try to start it.

You said before that you get the correct engine temp sensor readings at 80C. Do you get the correct temp readings when the engine is cold? Does the 300E have an intake air sensor? If so, have you checked it?

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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.