Help with automatic block entity updates.

So, I have a custom functional block that converts one item to another. The items that can be converted and what those items can be converted to is irrelevant and so I won't go into it.

The issue I am having here is, the only way for the items to be converted, is to have the GUI open. The moment that the GUI is closed, the converting stops. (It is an automatic converter)

I have tried adding the event listener of onPlayerTick and onEntityTick and onWorldTick but nothing that I have done works. All I need to know is how am I supposed to get the data to update without having the GUI open all the time.

If you want a picture just let me know. I will send one when I can.