I have swapped a b16a2 99 into my 99 ex coupe. i used the engine harness that came with the engine should be original engine harness for a si. When i bought it it came out of an eg coupe so it had obd1 gsr ecu. the kid threw in a obd1 to obd2 jumper harness that he had. Now my confusion is on the engine harness i have 2 plugs that go right in and the 3rd does also, only there is the exact same plug that is on my body harness so that i have 2. also the lime green plug on my body harness from the car have 2 spots for a group of wires. from the car there is only 1 group and from the engine harness there is 2. which means one whole half of that harness is not powered. i am trying to source a p2t ecu now to probably take away much of my confusion but if anyone really has any idea on this it would help me greatly. with my own diagnosis im thinking it has to do with my car being obd2a and the b16a2 being obd2b. all true info will be greatly appreciated and thanks.

 

sounds like you were given an obd2a harness. a harness out of a 99-00 si should only have 2 plugs at the ecu. is there a part # on the harness?

 

No part # but i think it is a 96 98 harness. would that cause this problem?

 

Why did you not simply use your EX harness? It's wired for everything already. You'd need to swap the dizzy plug to mate with the B16A2 dizzy and extend a few wires.

Done

 

I have a p2t ecu now and it seems like more than that with my harness. If I buy a b16a2 harness will that work with my body harness?

 

It'll work but do you still not have your EX harness?