Are you looking for a VX-Rom chip for the CA18DET? There's a Mine's ecu for the CA18DET currently for sale on ebay. This is the same ecu i'm using right now for my engine. Go check it out!
http://cgi.ebay.com/ebaymotors...35174
About your engine running too rich, what maf and fuel pump are you using? Are you getting a lot of black smoke come out of your exhaust?
Is your electric fan coming on when it's supposed to? I'm using a Honda Del Sol radiator and the electric fan (half the size of the 240sx radiator) and my engine temperature is perfect. I'm just using a manual switch to turn the fan on and off from inside the car and it works just fine for me. I would check to see if the water is flowing correctly and if the fan is coming on at the right temperature. Hope this will be of some help to you!