WHY are Haynes and Chiltons books SOOO WORTHLESS--4Runner Fuel pressure?

Ok so I made the HUGE mistake of buying a Haynes to help me out, and the Chiltons I borrowed is JUST as useful when it comes to information. Does anyone know how to check the fuel pressure for a 1987 22RE system?? Both of the books say to check the fuel pressure by unhooking the feed line at the fuel tank and testing pressure at the pump. This is fine if I wanted to know the fuel pressure at the pump, however I need to know what the fuel pressure at the INJECTORS is, if the pressure regulator is bad it wouldn't matter if the pump worked properly or not for pressure as the system would never build pressure at the injectors since it would just flow right back to the tank. So like I asked if you know how to check the fuel pressure at the injectors on an 87 22RE please let me know Thanks.