Macbook Pro not turning on! and if it does the Fans are maxed out!

Hello everyone, I have an issues with my 15" Macbook pro a1286 model with it not turning on or if it does the fans are maxed out at 6000rpms and the temperature sensors are not being detected. I am going to write out what I have troubleshooted so far and then explain what is going on.

Let's begin with when this all started, I was replacing the thermal paste on my old logic board and after about three weeks that logic board finally gave out. So I bought a brand new logic board from Ifix it and installed it, at first it didn't start, so I traced my steps and found that the Keyboard cable wasn't connected fully, after pushing it fully in, the macbook started up!! YAYY! not quite, the macbook booted up with the fans automatically spinning at max capacity which is 6000rpms. After booting into my hard drive (el capitan 10.11.6) I noticed that my battery isn't being detected and the temperature and fan sensors are not being detected. So I opened Mac fan Control and the application said no fans detected, I went into system report and found that the power tab isn't displaying the battery specs. So I went ahead and shut the macbook down and performed a System Manager Control Reset, and the Macbook booted up perfectly normal, the sensors and fans were detected, and the battery percentage was showing and the specs were showing in system report, so I thought everything was okay until 10 minutes later when the macbook randomly turned off on me, after that It wouldn't turn back on, I tried doing multiple SMC resets and RAM resets (CMD + P + R) and nothing was working, I disconnected the battery and charger and kept repeating on doing so, eventually after pressing and holding the power button over a dozen different times the macbook turned on again, but in the same state as before with the fans automatically spinning at 6000rpms and no sensors being detected again. I installed two new fans and a new hard drive and tried booting it up again and it does the same thing, the charger light will be random too, it'll sometimes be green and other times be amber or not work at all, its unpredictable. My Macbook has never been anywhere near liquids and worked perfectly fine before the first motherboard died on me. I am using the macbook as I write this, It works flawlessly besides the startup issues and the fans being on 6000rpms the entire time i use it, It hasn't done unexpected shut downs only that one time when I did the first SMC Reset, and SMC no longer fixes the issues like it did the first time i attempted it. Any ideas? and my macbook doesn't start if the battery is disconnected, if the battery is in the macbook it will start but if i just connect the macbook to a power source and disconnect the battery it will not start. I hope I gave enough details that someone can help. Thank you in advance!