Name:   MrHodja - Subject:   Slight Modification Date:   10/26/2015 6:42:45 PM

I don't think a metal detector will work beyond an inch or two of soil.  Lake Plumber has a "Cadillac" model detector and could probably speak with more authority on that.

Building on GF's fish tape suggestion, why don't you put a fish tape down the pipe until the clog stops it, mark the fish tape at the entry to the pipe, then pull it out and measure how far the fish tape went into the hole?  If you have a fair idea of the course of the pipe you could dig at that point.  Heck, you could just lay the fish tape on the ground above the pipe run and leave the tape measure in your tool box!

jes sayin'.....