my 89 audi 80 wont start. help me :(

well the title sums it up. i have a 89 audi 80 and all it does is crank over. i found that if i unplug the coolant sensor i can get her to start and run. so i replaced the coolant sensor but its still doing the same thing. any ideas i have to get her running. this is my first audi. but i have many early water cooled vws and thought this looked like a simple car to fix. i guessed wrong. please help me. by the way it has the 2.0l 8v with a auto trans not a quattro. thanks in advance
chuck