I have a 99 Civic Ex with a 98 gsr motor in it using s 99 civic si ecu. No more butterfly valves because of the ecu but the car will not run right. All of the wiring under the hood is done right. There are no codes and the check engine light is not on. Do you have to change some of the pins in the ecu for the car to run right. First off it will rev to 6 grand on its own when you first start it. Then it will go back down to 1000 rpms and idle between 2 and 4 thousand all day long. Everything works though the fans kick on and like I said no codes. It was hooked up to a obdII machine and not one code came off it and like I said the check engine light is off. Really confused here this is the first obdII motor swap I have done. All the other swaps were obdI and the cars worked fine. Not sure if the ecu needs to be repined.

Any Help On This One??