I have a 91 civic dx automatic that I picked up a while ago. My friend is swaping out his 91 SI motor out of his hatch and he is giving it to me. I know about the swap stuff since I had a 98 civic with a b18c in it, but this is a little different I guess. I want to know what I am going to need, for the complete change over. Am I going to need to chage the wiring harness ?

 

you must use your DX wiring harness and make the DPFI to MPFI wiring changes on it - you cannot use the Si engine harness in the DX

 

FourthGenHatch has a good description of how to do it on his web page:

http://www.fourthgenhatch.com

Look under Technical:How To:MPFI Wiring