BMW: Starting and stalling problem, 1988 bmw 535is, accessory line

Question
What is the possible cause why my car (1988 BMW 535is) stalls,and will not restart right away, however sometimes it will,after sitting for a few days. On two ocassions, on the advise of my mechanic,I have changed the computer. It starts up after changing the computer, but a little while later it shuts off, and the problem starts all over again will not restart. Another problem that also develops, should the car sit for approx three days, the battery goes dead.  

Answer
Sounds like faulty wireing... I would suspsect something is causing your battery to drain like a 12V+ wire that should be tied to the accessory line is prob. tied to a 12V+ constant feed of power... faulty cd player wiring etc.

I would have the electrical system checked out. As far as the faulty starts, it could be related, lack of voltage to the fuel pump.

Hope this helps,
Emanuel