Pumping the throttle does not help, But pressing it fully down might the throttle position sensor senses this, if it starts with full throttle that is putting the ECU into anti flood mode, although there isnt one as such on the motronic systems.
Next time, try holding it fully down and not pumping, pumping has no effect on an injection engine, if that helps, i would say its likely overfueling but with these injection systems its most likely a dirty throttle body, check the crank case vent system isnt pusshing gunk into the throttle body, its going to be something silly like that i recon.