Does anybody know how I can make a 3D game engine, or at least tell me where to start.

perhaps you do not realize that there are entire books published on this subject. there are also dozens (hundreds...thousands...) of open source 3D engines to look at.

in a less harsh tone... you proabaly want to take a look at this stuff on a Windows or Linux platform before you try something on a system like a ds or a wii.

that isn't even optional. Practicing 3d on a PC first is as crucial as practicing firing your gun before jumping into a war zone.

of course it is optional... this is homebrew. Of course, if you ever want to finish anything then it helps to know what the hell you are doing.

Got a question for ya.

What, do you feel, needs to be improved in the existing gaming engines, that you need to create one from scratch? Do you have any concrete, specific ideas for it?

And, if you actually don´t, then why not using the tons of existing ones for your game?

Can you give me a list of engines that work with wii.

No... but Google can. Google is your friend. Try it