A little background: I have a us ek9 hatch (ej6) and had a us b20z2 in it with a 96 (or 98 I forget) spec gsr hydro tranny. The engine lost compression so I pulled it to inspect it and possibly machine it if necessary, but it was too far gone for machining so I got a jdm b20b high comp motor. I changed the intake with my us one and replaced the oil pump with a us spec one to run my sensors from the us crv harness that I had previously, but can't run the knock sensor since the block isn't drilled for it.
Everything is in and hooked up and I turned the key and I heard (or thought I heard) the starter spinning but not engaging. I got it bench tested and the starter is good. So I put it back in and I jumped it in the engine bay. Then I realized the electric motor I heard was the radiator fan not the starter. I tried a couple things and fast forward where I'm at now is the starter is not hooked up in any way and the positive lead is off the battery, but even so if I jump the starter off the battery the fan motor kicks on. I feel like this is related to the problem of my starter not engaging.
Anybody have any helpful troubleshooting suggestions?