Having in hand the shape of the road and rural roads in the target region, followed the workshop documentation is available in pgrouting the site, I created the required fields, ran the pgr_createTopology, and other verification queries pgr_analyzeGraph and pgr_nodeNetwork, obtaining return "OK" in all of them.
QGIS using the BD Manager, to perform queries can not obtain routes from all nodes to all nodes, just a few return a possible route and only in segments almost completely straight.
I tried using the plugin pgRoutingLayer produced by Anita Graser and Ko Nagase, but the result is identical to direct SQL query.
I am using the pgr_djikstra to locate the route.
Does anyone have any idea what could be wrong? The following image with found and not found route.