After instaling motor and box in to my ef3 civic
do I use the b16a1 engin loom?
and do I use the loom off the b16a that plugs in to the b16a ecu?

the plugs that plug in to the ecu do they need to be replaced with the b16a loom inside the car?

just need to know really if I have to change the loom inside cabin and motor?

thanks heaps, it's real hard trying to work this out

 

The simplest method to do the wiring is to add the required wires to the existing engine loom, extend plugs where needed to reach the new locations for some of the sensors, and add wires to the chassis loom for plugging into the ECU.

The method you suggest is an awful lot more work, and unnecessarily complicated.