93 Blazer fuel pump

Do you not hear the fuel pump run for two seconds each time the ignition switch is turned to ON (or, RUN)? You know that there is no fuel pressure because…? Have you changed the fuel filter? You should.

The problem may be electrical. To find out if the fuel pump CAN run, there is a “prime connector” that you can run a +12 volt hot-wire to and power the fuel pump. The one-wire connector may be near the fuel pump relay, in the engine compartment. It’s just a single wire that looks like it didn’t get connected.

The oil pressure switch supplies power (12 volt) to the fuel pump when oil pressure closes the switch. The fuel pump relay also supplies 12 volt power to the fuel pump when the engine computer energises the fuel pump relay.

If hot-wiring the fuel pump, does make it run, there is a wiring circuit problem. You need a wiring diagram to know which wires to check, and a multimeter (or, test light) to check for power for the fuel pump. You don’t want to change a good fuel pump because you didn’t assure it has electrical power (Well, OK, I don’t want you to.).
Here is some information about checking the fuel pump: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Central+Multi-port+Fuel+Injection+System&partName=Fuel+Pump+Relay&pageId=0900c1528003d99a&subChapterTitle=Electric+Fuel+Pump&partId=0900c1528003d99f You’ll need to register at the autozone Web site to see the information.
Here are the wiring diagrams to do the troubleshooting with: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Wiring+Diagrams&partName=Chassis+Electrical&pageId=0900c1528003db5f&partId=0900c1528003da59 You need to allow about five minuets for the diagrams to load. Scroll down to Fig 47 and Fig 48. Print out, and trace the circuits.