Id say crank sensor is the issue too. it would explain why the tacho isnt reading engine speed
Check the the crank pulley... The pulley has an inner and outer part with a rubber strip separating the inner from the outer (which has the teeth the crank sensor reads). This is just a vibration damper... I had a similar problem on a 318i before, where the rubber had failed and the inner part of the crank pulley was spinning inside the outer.
It had been slightly slipping for a while.. car would bog down every so often when i planted the foot. eventually got worse to where the car wouldnt start. Took me a long time to diagnose it, only when I had a buddy of mine turn over the engine while I had a look around the bay, and spotted the crank pulley not spinning