I am new to evos and the evo i bought has the aem ems. I was wondering with that will the car still throw check engine lights if something is wrong and oil warnings and all that or no because its not the stock computer?

 

bummmp

 

it will not throw any codes as the OBD II system in the car is no longer active with the AEM in there, if you wanna go back to stock thou i have a stock ECU sitting here..

 

if i put a stock ecu back in that i get from here will my car not start??

 

At it's most basic level, you need to make sure the Immobilizer code stored in the ECU matches the code your key has - otherwise, yes, your car will not start. Do you know what your current immobilizer code is? Assuming those do match, then yes your car should start. How it runs will depend on what the tuning of the ECU you have is. If it came from a stock EVO (do those really exist???) then it should at least idle without a problem, assuming you haven't done massive modding to your own EVO (cams, turbo upgrade, fuel etc.)