I got a 96 civic dx hatch and just bought a complete b16a2 from a 99 civic si. it came with the wire harness and ecu so im guessing it'll be plug n play. I swaped the motor and the car ran good even though had a check engine light, but my rpm and speed doesnt work, the speed sensor works and the fuse is not popped. well my car just started to over heat because my fan doesnt work for some reason out of no where and around 2-2500 rpm it makes like studder noises and jus idles ther back n forrth and when I give it more gas pass that its cool. another thing is the ecu has 3 plugs but the wire harness only had 2?? I usually see 3 plugs on the wire harness but this one is wierd. well then I let it sit and drove it later on in the night with the heater on full blast, everything runs good again. wierd, but any ideas? please help. maybe if I used my stock harness and just hook up vtec and convert the iacv plug it'll run better or just buy a 96 ex wire harness?

 

oh and I was driving the car for a good hour or two before it start happening. it started to bog and studder first then started to over heat

 

96-98 engine harness is diff then the 99-00 use your stock one or get a 96-98 ex engine harness...99-00 is ob2b and 96-98 is ob2a...there u go..