Originally Posted by Wachuko

Back to the car and the fuel pump relay. Sometimes (at least in my case) it is not that the relay is bad, but that it makes poor contact in the socket. The socket where the relay goes in can expand (Each of the pin holes) and make poor contact with the relay.

What I did was to try to close up the contacts at the socket, and also expand the pins at the relay (pins on the relay are split so you can slide a thin blade and open them up a bit).

That cured my intermittent fail to start and shutting off while driving.

Hope that helps... and yes... this was after I replaced the relay, injectors, coil, fuel pump, cleaned every single fuel line, etc... etc... etc... before figuring out it was a poor contact at the relay...

This was on my '83 SC

Originally Posted by Vane

Hi,

Last winter I had similar problems, the fuel pump did not run.
Found this checklist.

http://www.hiperformancestore.com/Motronic.htm

My problem was that one of the crankshaft position sensors was
bad. Visually it was OK, but did not work. This you can measure
from the sockets in engine bay, left side. The 3 sockets close to
intake manifold.

The crankshaft position sensor is cheaper if you buy the Bosch
part in a BMW box. "Impulsgeber", BMW part #: 12 14 1 708 619

Let me know if you need any more info, but the change is pretty easy.