If you are talking about a round looking thing with one line out the bottom and two across the top and sits beside the fuel pump , It is listed in my old factory parts book as a " Valve" . Part # 112-127-405-A. It came on AD,AE,AH, AF engines. Not all engines had these and I can't recall anyone calling them a ck. valve. We thought they were some kind of pressure regulator. I DO Know they screwed up often and we were told to replace it or toss it. No harm ,no foul.[/i]