Ajax call to service adds extra information to URL

I went back to an old project I had waiting to go ahead. To my big surprise the ajax calls I am doing to a service are not working anymore. I tested the service in debug mode from Visual Studio and it is working fine but I am using thru my local IIS it doesn't.  I am not sure why but it appears to me that the IIS is adding some stuff in the URL
Looking at the trace listener I found this:
<Description>Incoming HTTP request to URI 'http://uluru/BienesRaicesSVC/RegionesServicio.svc/GetRegiones?_=1414764526615' matched operation 'GetRegiones'. </Description> and further down  
<Description>Query string parameter with name '_' was not used during parameter deserialization for operation 'GetRegiones'.</Description> The actual URL should be 
http://uluru/BienesRaicesSVC/RegionesServicio.svc/GetRegiones I don't know ho ...