china ls1 t56 wiring harness repair issues. HOW TO FIX Guide 4.8 5.3 5.7 6.0

So, I figured I would make a post to potentially help someone who might be having issues with a swap they are doing as the result of bad wiring. I have seen and have had friends who have purchased the cheap eBay ls engine harnesses. At less than 300 it is hard to pass up for some. After installing these in vehicles I have found 2 major issues that need to be addressed in order for them to function correctly. Specifically, the LS1 T56 nonelectric auto harness. First issue is the tach output signal wire is shorted/ connected to 12v power from the fuse box. This will cause tach not to work along with possibly damaging your tachometer. Second issue is the map sensor signal wire is also shorted/ connected to 12v power from the fuse block. This instantly destroys the map sensor and defaults the pcm to barometric pressure 100% of the time. This one will cause the engine to stay in one section of the ve and timing table resulting in a very poor running condition if run at all. I have no idea if this information is out there somewhere or not. Just what I have experienced myself. Figured I would share in hopes that someone who is not familiar with wiring can get their project running after purchasing one of these cheap harnesses.