I think around 90 they moved to the MAS relay for fuel pump power however on my 89 420SEL the fuel pump relay had a cold solder joint on the fuel pump relay which would cause the fuel pump to randomly get turned off.
On my 190E I had a simliar problem with the car turning off randomly. It turned out to be both bad spark plug wires and bad OVP solder joints. I resoldered the OVP and it has been fine ever since.
420SEL Randomly Stalling?
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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
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(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)
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