I have a working 3d engine but the primary problem is that is uses up CPU making it near unusable at high object counts or sizes, which I have observed to be much lower than other engines.

My question is this, is there anyway to optimize this engine or should it be changed for another concept, if so, can you recommend an engine concept?

Here's a link to the project though it may not be of much help
Here

What kind of method are you currently using?

Current method is a similar to a heavily modified wireframe engine. It calculates two points and then ques it up into a list where it is then sorted and then qued up onto a grid and finally being rendered.

I would suggest using a triangle filler to render your objects