OK i have a 1997 honda civic CX that used to have the D16y7 engine non V-TEC and I bought a D16Y8 engine but I used to have a P2P ECU for a manual transmission so no that I did the swap my engine revs up a lot and throws me a code the RPMS are from 1600 to 1800 up and down and the code is this one IAC Valve Circuit Failure P1508, well I changed the IAC and keep doing the same, well I disconnect the computer and put the non V-tec computer on and the car runs just fine would that affect to my engine to have a non V-tec computer till I get one that woks or just wait and wich ECU number will work with the D16y8 engine?

 

Did your old engine use a 3 wire iac and your new one uses a 2 wire? The iacs are all a bit different on all of the engines in that class. Using the wrong ecu should not be a big problem for a short time.