"No start" Caused by Failed Fuel Pump/Relay on Mercedes-Benz 420SEL

The fuel pump and/or fuel pump relay can fail, causing the car to crank over but not start. Proper diagnoses will be necessary to confirm if the pump or relay is at fault.

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Average mileage: 212,000 (199,000–225,000)
2 model years affected: 1990, 1991
4 people reported this problem
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problem details
1991 Mercedes-Benz 420SEL 225,000 mi,
the car started and ran but it would cut out and quit while on the road. I would shake the ignition key and it would start back up. I changed ignition switch (cutting out with dremmel tool). Problem still occured so I changed starter relay and no problem now.