the very early low spec bikes (with no brain to do any maths) came with a different pump with a special float - this is NOT the float or pump that came on bikes in 2009/2010
bikes with the trip computer got a ZFE Basic HIGH or a ZFE High - I believe a 2005 float machine got a ZFE Basic Basic, so its possible the programming on the cluster and inside its old ZFE is different, the pump different and thus its float logic incompatible with a normal bike
go on parts thing and spend days cross reffing parts and checking drawings - then give up and buy the Argentinian grown up strip replacement