How to Test a Fuel Pressure Regulator

Does anyone know how to test a Fuel Pressure Regulator in a 1997 Chevy Blazer with a 4.3L (w)? I have low fuel pressure and I am trying to figure out if the problem is the fuel pump assembly or the Fuel Pressue Regulator. Can anyone tell me how to test the Fuel Pressure Regulator? To get to this item I have to remove the upper intake manifold. I would think there would be a way to test that without removing the intake manifold.

Please help.

Tap into the fuel regulator with a pressure guage..the pressure should remain constant at idle and move up slightly when engine speed is increased.. if pressure drops then regulator is bad..

Do you mean tap into the fuel rail test port (the same port that I used to check the fuel pressure)? If it says 50 psi., (like it does, however is should say 60-66 psi.) and increases when the engine speed is increased, that tells me that the fuel pressure regulator is good. If the fuel pressure decreases when the engine speed is increased the fuel pressure regulator is bad.

Is my above analogy correct?


Tap into the fuel regulator with a pressure guage..the pressure should remain constant at idle and move up slightly when engine speed is increased.. if pressure drops then regulator is bad..

check the service manual to see what the correct fuel pressure should be...the pressure should remain constant..the regulator keeps the pressure equal at all rpm's so that the computer knows how much fuel is going into the engine...it shouldnt go up very much at higher rpm's...more that 3 or 4 psi..and shouldnt drop more than 1 or 2 when it comes off idle...and yes the port used to check fuel pressure is correct...the vehicles with the vortec motors had a problem with the regulator leaking...after preforming the check turn the key off and watch the gage..if the pressure falls rapidly you will need to change the regulator out..

correct fuel pressure is 56-60 for start, 61-65 at running...