Hello, I have an 84 633CSi. I recently had to replace the starter. The next day, I went out to start it and the engine would turn over, but when I let go of the key the car would die. I had it towed to a local BMW shop to be looked at. They told me that the new starter was fine, the fuel system was working fine, but they did say that the Ari Flow Meter was bad. Does this sound right based off of my experience?
If the AFM is unplugged, it will start and then die. Check that the wiring harness was not destroyed, piched, cut, or that the AFM is simply plugged in properly. If the timing sensor is bad (but the TDC sensor is OK) the car will do the same thing. The plugs for the reference sensors are often brittle and can be destroyed if molested, so check those too.