PHP live search issues

We are creating an in-house garage system with parts system built on top. Within our parts system we have a live search to get any required parts from our database - which holds 25000 parts. Our problem is the SELECT query we are using will not look at the other parts that are in the database and because there are 25000 records we have to have a LIMIT on the SELECT.

We have other live searches in other areas of the system that work with a LIMIT and still find information in the database.

I have uploaded a copy of the code being used for the parts invoice. The code for the live search we are having problems with is at the bottom of page 4. I have also included the code used to populate the dropdown and also the SELECT statement.