Hello guys! So I have a 2013 BMW M5 F10 with 137k km on the clock. Recently I did a full engine service & rebuild with forged connecting rods. The car ran fine but had a rough idle, tried to do everything to fix that but nothing helped. Local guys recommended for me to lower the engine and change the headers, my friend had a really good set of headers and got them for free and decided to change them. After they were changed we were not able to start the car...
After we disconnected one of the Camshaft position sensor the car started roughly and was running with misfires. Did a lot of troubleshooting locally, tried to change the ECUs (did not help), timing chain is adjusted and vanoses are fitted correctly (there was a thought that intake and exhaust vanoses were installed incorrectly) now the only thing that is left is for us to change the whole engine wiring... hoping that will fix the issue.
Do you guys have any experience in such case? What more can I look for?
