1994 Buick Century 3.1 v6 fuel pressure regulator

The fuel pressure on my 1994 Century 3.1 V6 is low ( 35ish psi). It should be in the 47 psi range. I’ve replaced the fuel pump with no change. Now, I’m working on replacement of the fuel pressure regulator. It is an absolute bear to change. The injection plenum casting interferes with the removal of the regulator in almost every way. I’m hoping if I disconnect the fuel return line the steel pipe will thread under the plenum and come out. Everything else is loose. Any help is appreciated.
Thank you,

1994 century 3.1 v6 fuel pressure regulator replacement - Yahoo Video Search Results

Go online to Mitchell Auto Repair Online Manuals - Vehicle Year Selection - Mitchell 1 DIY

Change the criteria as needed. It will provide all the steps you need to follow.

Start the engine and let it idle for 30 seconds.

Shut the engine off.

Remove the vacuum line from the regulator.

If gas leaks out of that connection, the regulator is bad.

Now start the engine, remove the vacuum line.

The fuel pressure should increase.

If it doesn’t, the regulator is bad.


If I recall 35psi is ok for fuel pressure at idle with no load. 47 should be the max regulated pressure.

With the engine warm and idling, pressure in the mid to high 30’s is ok. With the vacuum line removed from the regulator fuel pressure should increase to mid 40’s.

It sounds like the OP should be backing up and tell us what problem he is trying to solve. That is, what symptom caused them to start looking at the fuel pressure?
(Aside: note the modern use of the word “them”.)

From what I see, to remove the FPR on the 3.1 v6 you have to relieve the fuel system pressure, then remove the upper intake manifold before you can begin the process to remove it. So, yeah, it looks like a pretty big job. I expect your best bet is use whatever patience is required and remove the portion of intake manifold that’s in the way. Likely going to affect the throttle cable, EGR valve, heater pipe, ignition coil, alternator, various electrical connectors and vacuum hoses. BTW, be sure to use all the common sense safety precautions when working w/gasoline, especially having a big fire extinguisher at the ready.

BTW, good advice above, there may not actually be anything wrong w/the FPR. Are you certain you are testing it correctly? As long as there is no fuel in the vacuum line, might pay to have a shop give you an independent assessment first.