how to perform a three step fuel service + how to make a tool

Step 8: If your vehicle is equiped with a regulator and or fuel return hose...

vehicles that are so equipped  are a little more difficult to clean. on an open loop fuel system, ( has a return hose) the fuel return hose needs to be capped off. i use a thick vacuum cap. a bolt and hose clamp on a rubber return line can also work (be sure to isolate the fuel rail side) alternatively you could get a fancy hose clamp pliers from a tool warehouse and pinch the line off . the other important step is to remove the vacuum hose from the fuel pressure regulator and plug or pinch the hose off. if when you apply pressure to clean the system and fuel leaks out of the vacuum port of the fuel pressure regulator, the diaphragm inside the fuel pressure regulator is shot and needs to be replaced