I'm droping a first gen b16a in to my 93 civic, the motor running but it wont idle right. its a b16a long block but has a 93 ls throttle body with the Fast idle valve on it, and a ls IAC valve. Does anyone know if the b16a and b18b IAC Valve is the same, they look a little diffrent. Or if the b18b throttle body is causeing the problem? The knock sensor is also not hooked up if that could cause is?

 

all check the vacume hose on the map sensor

 

That is exactly what I would do. I recomend that prior to doing a swap go head and replace all tha vacum line with new ones maybe even dress it up a little. This is a common problem with swaps and its easier to replace all before hand rather than trouble shoot a leak after the install. I know its to late know but live and learn. But I would start with the vacum line. It could also be the map senor. I know that first hand. Good luck and happy troubleshooting