Fuel pressure regulator location

[gwtolbert]

Has anyone replaced a fuel pressure regulator on a 4.6L? I found the fuel pressure damper on the passenger side fuel rail but can't find the fuel pressure regulator. My Haynes book say 2003 and earlier, it's in the tank. I hope they're wrong. My motor runs rough and misses at idle and on the road. The codes started with multiple cylinder misfires and I've had a variety of different codes after that. I've replaced the plugs, coils and fuel filter. Checked the fuel pressure and got 65lbs running but when you shut it off, fuel pressure goes to zero immediately. That's why I suspect a fuel pressure regulator. Any help would be appreciated.

 

[matt0248]

The FPR on my 02 4.6 is on the front of the passenger fuel rail. it has a vacuum hose going to it. You may have a bad regulator or a check valve in the fuel pump module in the tank.

 

[gwtolbert]

The FPR on my 02 4.6 is on the front of the passenger fuel rail. it has a vacuum hose going to it. You may have a bad regulator or a check valve in the fuel pump module in the tank.

Thanks for your response. I was beginning to think that no one has had to deal with this issue. I think what you're describing is the fuel pressure damper. I have the same thing on my truck and it tested good (no failed diaphram). According to the information I've found so far, the fuel pressure damper functions to control fuel pressure oscillations in the system. None of the regular parts stores (Autozone, Advance, NAPA,Checker etc) show a listing for a fuel pressure regulator. This usually means a dealer only item. I've had good luck with www.rockauto.com so went there to check for the part. For the 2002 4.6L motor they show both a fuel pressure damper and a fuel pressure regulator with photos. They look similar but they are 2 different parts. This leads me to believe that there is a fuel pressure regulator elsewhere on the truck. Haynes says 2003 and earlier its in the tank. The part that rock auto shows appears to be one that would not be in the tank. I was hoping someone had already been through this exercise and could tell me for sure where the fuel pressure regulator is located. I'm going to drain my tank next and add fresh fuel just in case I have bad gas. I'll update this thread as I progress. Thanks for your input.

 

[matt0248]

There is an easy way to tell. check the fuel pressure with the engine running, then unplug the vacuum line, if the pressure rises it is a regulator. A dampner will not control pressure and should not have a need vacuum hose.

 

[gwtolbert]

There is an easy way to tell. check the fuel pressure with the engine running, then unplug the vacuum line, if the pressure rises it is a regulator. A dampner will not control pressure and should not have a need vacuum hose.

Hey, thanks for that tip. I'll try it. It would be really great if it was that easy. I really don't look forward to dropping the tank. The procedure in the Haynes book looks really involved, although if I drain the tank that would be the right time to do it. Thanks.

 

[Explorer Pete]

Just a note; You don't need to drop the fuel tank. You can open up a hole in the floor to access the fuel pump and then screw in a cover plate to close the hole, like I did with my 02 4x4 XLT when I had to replace my fuel pump. Pete