"79" 733 starting problem

I have a "79" 733i and until recently it was running as normal as it did. I drive a big truck and for a few months was gone about a month at a time. One time when I came back it wouldn't start. Just crank & crank, I removed the air filter housing and used spray starter and it cranks right up but won't keep running. Fuel problem! I checked and the pump does work but not when you crank it up. Question could the ignition switch have gone bad or maybe the key worn so some of the starting procedures aren't working correctly? All lights and other electrics work just like before, and I tried hard wiring the pump and still nothing(although the pump was spinning)
Any thoughts???

Your car uses an L Jet Bosch system.

Here is a link to an e12 L Jet information site.

http://www.firstfives.org/faq/ljet/jetronic.pdf

The ignition controls the main relay, which controls the fuel pump relay.


To bypass the fuel pump relay you can short pin 30 to 87 bypasses the relay.

To bypass the main relay you can short pin 30 to 87 bypasses the relay.


http://members.roadfly.com/kcroncarter/bmwetm117.jpg

Later,