new to this forum but a long time Honda owner . currently have a big issue with a new used motor for my 91 crx hf model. the used motor came out of a 88 crx both motors are d15b6s. everything swapped out no problems. tried different combination of some major components but still have a motor that runs super rough. any help welcomed

 

have you checked the timing belt position ?
its sound like a timing issue

are you sure the 4 cylinders have fire ?

 

Can you be a bit more descriptive when you say it runs super rough? Have you done a basic tune up recently? Or do you know when the last one was done?