E30 320i (L-jetronic) - Help what powers the tacho???

Are you sure its a E30 320i? I didnt think BMW produced a E30 320, an E21 320 yes if I remember right. But on my '85 318i the tachometer is powered by the distributer, think is called the pusle generater but I could be incorrect. My car does have the Bosch L-Stronic fuel injection system. Hope this helps.