John T
 

My 1995 S420 W140 has been missing then stopping after 20 mins driving while slowing up or in traffic it then refuses to start for about 45 mins-60mins.
Reading past problems I have changed ignition distributor caps and rotor arms
up to now ok but past posts read say maybe a fuel pump relay problem or
overvoltage protection relay.
Please could anybody suggest a cause or the location of both the fuel pump
relay and if fitted over voltage relay.

Regards John T

Your engine doesn't have an OVP.

Have you checked your Crankshaft Position sensor?

John T S420 W140 1995
 

Hi Suginami sorry I have taken some time to reply but after changing the
distributor caps and rotor arms up to now still ok fingers crossed.
Thanks for your suggestion about the crankshaft sensor may have to try this if it fails again.

Regards John T:)

What testing have you done?
 

What testing have you done?
You can spend thousands of dollars on parts, and still not solve the issue.

MB Engine Wiring Harness Failure
http://www.peachparts.com/shopforum/general-information/128181-mb-wiring-harness-failure-post927185.html#post927185

No-start help for beginners
http://www.peachparts.com/shopforum/tech-help/143414-no-start-help-beginners-post1076969.html#post1076969

Have a great day.