Question
the Zones for my irrigation will all come on at the same time or it will skip zone.what do i need to do or what may i need to replace?

Answer

Selenoid Hi Tom

If this is a electric valves system, probably the selenoids don't close the valves and all remain open. check the selenoid make sure all are on off position. I the problem continues, check the selenoids plungers (see picture)if they seen wear, replace the selenoids. Or probably you have valves issues, go to http://www.irrigationtutorials.com/faq/repair-valve.htm to find out the fixing.

Regards
Guillermo