I recently replaced my head gasket, after i got everything back together my car wont idle. Engine is jdm b16a. I haven't put coolant in it yet because i dont know if i will need to take it apart again. It runs if i give it gas then engine throws a code. I jumped the pins to read the code but the cel didnt flash it stayed solid. So i dont know what code it's throwing or what the problem is. Could the timing be off by a tooth or two?

 

You mean, of course, that you filled the cooling system with plain water for testing. Never run at all with nothing in the cooling system. Plain water causes corrosion, which will be serious damage if used for more than a couple of days.

The symptoms you describe are often because the ground wires on the thermostat are not secure, or the sensors are plugged in wrong, or the spark plug wires are out of order. Also of course double check cam timing. Since the engine runs at all, you can check spark timing with a timing light.