WordPress + Code Igniter Config not working (no replies)

Could someone look over my configuration? It appears I am missing something that is causing it not to work. I have a Code Igniter application that runs from the root WordPress folder fine with Apache, but it is not working with my Nginx configuration.

The WordPress root folder is: /var/www/vhosts/wordpress

The Code Igniter root folder is: /var/www/vhosts/wordpress/code_igniter

My config is:

root /var/www/vhosts/wordpress;

location / {
try_files $uri $uri/ @wordpress;
}

location @wordpress {
try_files $uri =404;
fastcgi_pass php;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include /etc/nginx/fastcgi.conf;
}

location ~ /code_igniter/ {
try_files $uri =404;
fastcgi_pass php;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root/code_igniter/$fastcgi_script_name;
include /etc/nginx/fastcgi.conf;
}

location ~ \.php$ {
try_files $uri =404;
fastcgi_pass php;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include /etc/nginx/fastcgi.conf;
}