Help. 1986-420 Will Not Start
 

Does the Mercedes 1986-420SEL have any safety mechanism to automatically shut off the fuel pump? Like maybe in a wreck> Is the system tied to the oil pressure?? Jim

No it's not tied to oil pressure, many people believe this, but not true.
More than likely it's a bad fuel pump relay. It is between the double firewall area behind the engine on your type of MB.
There are two relays that look about the same.
One of them says "Klima", that's NOT it, it's the other one, it should show an engine RPM and also say "8 zyl" (cylinder) on it. You could jump 2 of the sockets on the plug-in to see if you can get power to the pumps that way, but just for testing, don't leave it plugged in that way.
Gilly

Or if you are just wondering about this in general (I see you are not a newbie around here now), no the pumps operation is not connected to oil pressure nor is there any crash deactivation. That came way later than that.
Gilly

Thanks
 

Thanks for the information. The car in question is just a friends new purchase and it has some issues. I usually just mess with diesels. The problem of starting has been solved. Just a bad fuel pump relay connection.. Jim