Having just been through a fight with the tachymetric relay in our 1983 505 with the XN6 motor and Bosch K-Jetronic fuel injection, I figured that I'd post some of my experiences in case they're of any help to someone else in the same boat.  This post is long, so if all you need are replacement part numbers skip to the end of this post. For anyone unfamiliar with the tachymetric relay, it controls power to the fuel pump and its failure will leave your car utterly stranded.  This happened to