1990 300E

My car won't start except when I poured little fuel in air intake. I replaced fuel accumulator & fuel pumps work. I took the car to dealer for checking inly. He said that it requires replacing distributor cap & rotor.

My question is: (a) What does cap do in preventing start-up? (b) Can rotor work normally when I pour gas in air intake and not when I try to start normally?

Your help will be appreciated.