I have a 2014 silverado v6 but i upgrade to a v8 motor and now wont start alredy change computer and harness but no look does someone here know something a bout that help please

 

Did you just swap the computers or did you actually have it flashed so that it could run correctly?

There is security stuff that will stop it from running and that fact that if you used your old 6L80 transmission you need to have the TCM flashed so it matches on both computers.

 

Yes i did flash the computers but neither one work they told me i have to replace all wirering harnes

 

All wirering harness inside the cab and under the hood

 

Did u know more a bout the swap on this kind of vehicles 2015 chevy silverado

 

Why didn't you just flash the computer? And did you get it going? What did it take? And how big of a headache? The reason why I have so many questions is that I have a 2014 rcsb that I picked up dirt cheap and now I'm looking into swapping the 4.3 to the 5.3...

 

long story short I need help getting my truck running right, I swapped a v8 into my 58k miles V6 2015 gmc sierra 4x4, donor truck was a 2017 V8 4x4 i'm using a complete 2015 engine harness, 2015 v8 ecm vats deleted and 2015 fuse box , runs smooth for about 30 min at idle with all kinds of codes including CEL light ,engine power reduced on the information screen and other lights then shuts off , if I disconnect fuse box battery cable it starts back up I have driven it up and down the road but it struggles to switch gears as I have seen this on other trucks with the engine power reduced code, I had a guy come out to try to program it a couple of years ago but all he did was screwed the mileage on it now it just shows lines like this - - - - - I wish I knew some shop in my area to take it to I live in san antonio tx , just notice some of the accessories don't work ,mirrors, tow and haul button, and running low beam lights come on the after a few seconds flicker and turn off some times at night im almost sure is that there is wiring pinout issue some where but not sure what to look for or where to start

 

Nelson performance is in SA. Bet they can figure it out.

 

Did you move your tranz back to make it fit or how did you get it to line up

 

Did you get the engine to fit?