i have a 97 civic hb cx that i will be putting in a obd2 b18c1 and i want to make it in to an obd1. i no that i need a under dash wiring harness for the ecu, but what modifications do i need to do to the engine harness?
and if i use a 96 ex engine harness will it work in this occasion so i dont have to wire vtec and the other connections needed?

 

If your engine and car is OBD II then leave it that way. Don't change the OBD type. Otherwise you have a wiring nightmare.

 

sionce its a ek, run everything 0bd-2 then at the ecu get a jumper harness and run a obd1 ecu. that will save you time and a headache