I once spent 2 days messing around at work with a Fiat grande Punto turbo that was the same, crank but not start, kept flooding the plugs. Fiat field engineer came out and after a while suggested we test the fuel, drained some out and set fire to it (!!!!) it burned but very slowly and made an oily mess on the floor afterwards. Drained the tank, put fresh petrol in, fresh plugs and it was away!