If the problem is after your zone valve, such as a clogged or pinched line, there is a couple of things you can do. First of all, if the zone worked properly this spring, a pinched line is pretty unlikely, but still a possibility. If the line is clogged, you will need to remove the sprinkler heads from that zone and flush the line of any debris. If none of the sprinkler heads pop up at all, you know the clog or pinch is somewhere between the valve and the first head on the zone.
Tony Posey
Ridge Run Landscapes