I am a bit confused, you say L-jet, but a E12 520 (m10 engine, right?) should have the mechanical Kugelfischer injection.
If so, congratulations, you have quite a rare E12. If not, you can ignore everything I write after this
If so, forget about anything you know about regular (common rail low-pressure) gasoline injection systems. The Kugelfischer resembles more a classic diesel injection with a rotative high pressure injection pump.
The injection pressure is high, 400 - 500PSI so be careful playing around.
I'd first check the ignition on the car (timing), leads, spark plugs, then indeed locate the cold start injector, and check if it stuck open.
I have never seen such an injection close-by, but judging from pictoes and drawings, the cold start injector is on top of the intake, near the round cap, in the picture below I can see what I suppose is the black fuel hose and the electrical wires going to it:
http://cache.gawker.com/assets/images/1 ... tiieng.jpg
I recall that the injection pump itself can give trouble after a long period of inactivity, some plungers / valves get stuck, but supposedly just running the engine will fix these issues in time.
Be careful / selective of who you let work on this car. Not many people understand these systems, look for a specialist. Post on a board for 2002, the 2002 tii had the same engine, there is more knowledge out there.
2 more quick links about Kugelfischer:
http://arrc.ebscohost.com/ebsco_static/ ... UEL_IN.htm
http://www.jc42.dial.pipex.com/alpina/I ... iption.htm
