Canine: Wordpress Custom Searches mentions

Half a year later, Andrew Bacon was having trouble with searching custom fields, and asked for help. I responded:

Sorry for the delayed response, I was on vacation for a bit.

It's been a little while since I worked with the above method: I ended up using Pods for the project mentioned above, and the project ended up getting canceled anyways. I'm not sure why it wouldn't be working for you. Does it work with the form and named fields? Do you have your permalinks set up unusually? Keep in mind that dates in custom fields will be stored as strings, so normal date comparisons won't work. If you have fairly complex data needs, you could try Pods. It takes a bit of figuring out, but can be quite powerful.

The next year, Rotten Elf asked if this method still worked in WordPress 3. I responded:

I haven't used this method on any new sites and the site I originally did this for was never put into production. I still have the site in test though. I upgraded it to 3 and it still is working, I haven't needed to change anything. It should work for you, good luck.