Leaking Fuel Pressure Regulator Replacement- 3100 and 3400 Engines

When the fuel pressure regulator(1) on the 3.1 and 3.4 engine fails, fuel leaks into the vacuum hose at the top.This condition causes a hard start, long crank time, runs rough when started, and can also cause a stall condition when coming to a stop.

This also causes poor fuel economy.

Use these pictures and instructions in the replacement of the regulator. The upper intake manifold plenum does NOT need to be removed.

1- Fuel pressure regulator
2- A 15/16 in. wrench
3- Hold down the throttle lever to gain access

How to replace fuel pressure regulator (FPR) on 3.1l and 3.4l v6 engine

1- Fuel pressure regulator
2- #40 TORX socket
3- Extension
4- Hole in throttle cable bracket
5- Ratchet

Leaking fuel pressure regulator can cause hard stating, stalls, gas odor, misfire code p0300

Great info! I think on my 1993 Buick 3.1 the regulator is under the intake tho?
 Yes, on the older models the fuel pressure regulator is located under the upper intake plenum manifold.

What should the pressure be on a 2003 Buick Century?
 A good rule of thumb is 45 PSI.

I have the 3.1 v6 Chevy Malibu. I took the hose off for 3 mintues, didn't see any fuel come out to suggest a problem. However, whenever the hose is put back on, I can hear humming while I'm sitting in the car with it running. I take of hose, no hum. Strange? Should I replace the regulator. Note: Just did fuel pump 4 days ago because it failed, also did fuel filter and pump relay just as a precaution. BTW, the sound is not coming from the back or the fuel pump, but in the front.
 If this is an older 3.1L, then yes, replace the fuel pressure regulator. There was a design change years ago for making noise.

The fuel pressure regulator is a vacuum operated diaphragm relief valve with fuel pump pressure on one side and regulator spring pressure and intake manifold vacuum on the other side. The fuel pressure regulator maintains a constant pressure differential across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as the engine vacuum drops.


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