128i n52 2009 not starting
(bmw 128i e82 coupe 2009 n52) couple weeks ago my car just randomly wouldn’t start. changed ground wire first, didn’t work, then changed the starter. worked for a week and then stopped starting again. changed the starter again and half way through putting everything together tested it. it started fine. then put everything back together and no start. took some things apart again and tried and nothing. neighbor said it was the brand (SEG) but i got it on FCP euro. got a new starter (Bosch) and installed it. nothing. tested the volts on the relay, the battery, the white wire connecting to the starter, jumped the battery, jumped the relay, and nothing. super confused and lost and i don’t know what to do next
the only thing i could think of is that the ground wire wasn’t completely clean shiny metal to metal and i didn’t use new bolts, could that be the problem?