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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 54019
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I have a 1990 Mercedes 420 sel gasoline that dies at low

Customer Question

I have a 1990 Mercedes 420 sel gasoline that dies at low speed and with in a minute or two after starting. It starting to it more often. the other day I try to start it and it would run only a second and die. tried five times an only run a second and die. two days later it starts up fine runs great. It might not do it again for several weeks.
Submitted: 1 year ago.
Category: Mercedes
Expert:  Marty replied 1 year ago.

Hi, without performing some tests for ignition spark and fuel pressure it is hard to say for sure what may be happening but the symptoms you describe sound very much like a faulty fuel pump relay. When the car won't start the fuel pump relay can be removed and bypassed to test for a faulty relay or you could simply replace the relay and see if it fixes the problem.

Let me know if you have any questions.