Sorry but i tryed to search and came up with nothing. What numbers should i be looking for and does anyone have any helpful tips??

thanks

by the way i have a 99 4.3 vortec

 

Hmm... Don't know what terms you used to search, but 'fuel pressure' gave the appropriate threads in the top few spots...

But to answer your question, 55-60psi is where it should be.

What are you looking for tips on? Testing the fuel pressure? The fuel pressure test port is located on the larger fuel line behind the throttle body. Remove the cap and it'll be a shrader valve looking very similar to the air valve on your tires. You need a fuel pressure guage to test it. Some autoparts store have a loan-a-tool program where you put money down on the item, then when you return it, they return your money. Install the gauge and turn the key to the ON position. Take a look at the pressure. Turn the key off and see if the pressure drops over the next 15-30 minutes. Start the truck up and see how the fuel pressure reacts to various engine loads. ETC...

Anything more specific will require more information on what it is that you are trying to accomplish.

 

This is from the GM service info for 1999 Blazer with a 4.3. The pressure should be 60-66 psi when the pump is running (key on, engine off) :

When you turn ON the ignition switch, the Vehicle Control Module (VCM) turns ON the in-tank fuel pump. The pump remains ON as long as the engine is cranking or running and the VCM is receiving reference pulses. If there are no reference pulses, the VCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops. The VCM will also turn ON the fuel pump for 2 seconds when the ignition is turned to the OFF position. An electric fuel pump pumps the fuel through an in-line filter to the Central SFI unit. The pump is attached to the fuel level meter assembly inside of the fuel tank. The pump is designed to provide fuel pressure above what is needed by the fuel injectors. The pressure regulator keeps the fuel available to the injectors at a regulated pressure. Unused fuel is returned to the fuel tank by the fuel return pipe. Test Description The numbers below refer to the step numbers on the diagnostic table. [ol] Wrap a shop towel around the fuel pressure connection to absorb any small amount of fuel leakage that may occur when installing the fuel pressure gauge. Turn ON the ignition leaving the engine OFF, the fuel pressure should be 415-455kPa (60-66psi) when the pump is running. This pressure is controlled by a spring pressure within the regulator assembly. The fuel pressure that continues to fall is caused by one of the following items:[*]The in-tank modular fuel sender is not holding pressure.[*]The fuel pressure regulator valve is leaking.[*]A Central SFI injector is leaking.[*]Fuel line is leaking. [/ul][/ol] [ol] If the fuel pressure is less than 379kPa (55psi) at idle, it falls into the following 3 areas:[*]The pressure is regulated but less than 379kPa (55psi).The amount of fuel reaching the injector is sufficient, but the pressure is too low. The system will run lean, hard starting cold, no start, overall poor performance, and may set a DTC. Refer to Engine Cranks but Does Not Run[*]A restricted flow causing pressure drop -- Normally, a vehicle with a fuel pressure of less than 300kPa (44psi) at idle is inoperable. However, if the pressure drop occurs only while driving, the engine will normally surge then stop running as the pressure begins to drop rapidly. This is most likely caused by a restricted fuel line or plugged filter.[*]A leaking or contaminated pressure regulator valve or seat interface may not allow the regulated pressure to be achieved. [/ul][/ol] [ol] Notice DO NOT allow the fuel pressure to exceed 517kPa (75psi). Excessive pressure may damage the fuel system. Restricting the fuel return line allows the fuel pressure to build above regulated pressure. With the fuel pump commanded ON, the fuel pressure should rise above 455kPa (66psi), as the valve in the return line is partially closed. When the engine is idling, the manifold pressure is low (high vacuum) and is applied to the fuel pressure regulator diaphragm. This will offset the spring and result in a lower fuel pressure. This idle pressure will vary somewhat depending on the barometric pressure; however, the pressure at idle should be less indicating the pressure regulator control.[/ol] [ol] If the injector(s) is not grounded, physically remove suspect injector(s) and inspect for a fuel leak while system is pressurized. If the fuel injector(s) are not leaking and fuel pressure is not holding, the fuel pressure regulator should be inspected for a slow diaphragm leak.[/ol]