like the title says my brothers 02 civic wont start. he has a 02 civic 4 door and he just but a 05 civic ex motor into it because his old motor blew but it wont start now... he told me it has spark the alternator is new and so is the batterer. but if anyone know whats wrong with it can you help.... thanks

 

Your description is rather vague..

Is it an automatic, or a manual?
Does the engine turn over, or does the starter just click when you try starting it? Or does it do nothing at all?
Are there any illuminated indicators on the cluster? Does the "little green key" light keep coming on?
Can you hear the fuel pump prime the system when you turn the key ON?
Have you checked the fuses, grounds, connectors, etc?
Are you using the stock ECU, or did you change that too?

It could be a number of things, but it's likely something rather simple.

 

yes my brother is a big honda guy he knows pretty much eveything... but his not into computers so im writing this for him... its has a 5speed manual trans, he said it wont turn over, it doesnt do anything.... and i dont know about 02 civic much neither does he, but he just got it for 400 dollars.... i dont know if he has check the main relay fuse but ill tell him and see what happens.. thanks for your help