Hi there, thanks for your time.
I got some progress in my problem, I did those all resets ( NVRAM, SMC ) and starts with one DIMM (8gb), runs great, so I felt lucky and tried to put the second DIMM, voilá no Beeps, but stucks on login screen, after put my password, 10 secs later, loops on apple logo and came back to login screen... Took one DIMM out and runs great, I get notified about apdate of high sierra, I did. I need to go out of my home and left the MBP on doing the update, later I upgrade with news.... Both MEMs I am 100% sure that are working great. Could be some problem with EFI firmware, crossing my fingers LOL