The fuel pressure regulator in your Chevy Blazer is used to help keep the fuel system's pressure constant. If the regulator is bad, the result is often low pressure in the system. Symptoms can include a rough, sputtering engine, failing to start after ignition and worse fuel mileage. Replacing a fuel pressure regulator, like any fuel system component, can be a dangerous task because of the pressure within the system.
Relieve the vehicle's fuel system pressure by removing the fuel cap on the side and the fuel pump relay inside the fuse box, then run the engine until it stalls and continue cranking it for five to 10 seconds.
Disconnect the battery's negative cable once the pressure is relieved.
Remove the air intake resonator by disconnecting all connectors, ducts and lines connected to it--the ducts have hose clamps that need loosening--removing the resonator's mounting bolts with a wrench and detaching the ventilation hose from the valve cover.
Clean away all dirt and debris that is around the pressure regulator and fuel lines to prevent anything from entering the fuel system. Wipe it away with a clean cloth. If you use acetone, water or any other liquid cleaner, make sure you completely dry the area off.
Disconnect the vacuum line at the pressure regulator, the wiring harness at the front of the engine and the fuel return line. These should either come off easily by hand or have quick-connect fittings where you press on the tabs.
Remove the pressure regulator by removing its mounting screw; this can require a screwdriver or a hex wrench.
Make sure the replacement regulator has a new O-ring and lubricate this ring with a light coat of engine oil.
Install the fuel pressure regulator, tightening the mounting screw to 71 inch-pounds. Reconnect all other parts in reverse order of removal.
Re-pressurize the fuel system by reconnecting the fuel pump relay, turning the ignition switch to the on position for two seconds and turning it back on for five. Repeat the procedure with the switch multiple times.
