2001 honda civic vtec p1259 code
 

I bought the car needing a engine put a new ingine in it and the vtec wont work at all changed oil n filter changed the vtec silanoid and all changed oil pressure switch on the back of engine changed relays in the glove box checked all grounds in the engine compartment checked all wiring.. there is a o2 sensor code bc its asking for a nother o2 sensor but there no plug coming from engine harness. I can delete the code but it pops right back up with in 5 seconds of deleting it n without starting the car. And it was a non vtec car that was swapped over b 4 I got it. I put a ohms meter to the vtec wire coming from the harness says it getting 12volts but wont light up a test light dont understand that. And ran 12 wire to vtec silanoid and it does click on n off. If anyone can please help