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:confused: MY 1991 190E 2.6 HAS GOT ME AT A LOSS. A COUPLE OF WEEKS AGO IT STOPS RUNNING. AFTER GETTING SOME ADVICE FROM ANOTHER FORUM MEMBER AND RUNNING A FEW SIMPLE TESTS WE FIGURE OUT THAT MY MAS CONTROL UNIT IS BAD(FUEL PUMP RELAY). I PURCHASE A UNIT AND INSTALL IT AND... STILL WILL NOT START. COULD ANYONE SHED A LITTLE LIGHT AS TO THE NEXT STEP I SHOULD TAKE? ALSO IS THERE ANY WAY TO TEST THE NEW UNIT(MAS CONTROL UNIT) TO SEE IF IT IS BAD? THANKS IN ADVANCE.

You mentioned MAS and the fuel pump relay in parentheses...unless I'm absolutely incorrect or you have a pretty exotic MAS unit, the fuel pump relay is a separate component having nothing to do with the MAS.

The MAS may affect performance and possibly set off a CE light, but wouldn't contribute to the no-start issue.

The Mas Control Unit (89-93models) Incorperates The Fuel Pump Relay Or So I Have Been Told. I Think My Fuel Pump Is Ok . I Can Here The Pump Ingage When I Turn The Key On. But That May Just Be It Priming The System And Then The Mas Control Unit Takes Over , I Don"t Know. I Have Not Been Able To Crank The Car Up In A Month Or So With The Exception Of Three Timmes. Twice When I Was Trying To Figure Out What Might Be Wrong And It Just Turned Over And Once When I Jumped The Fuel Pump Relay With A Piece Of Wire Between The Fuel Pump Relay Plugs. All Three Times It Went Back To Not Starting Again.