Lexus082

Does your fuel pressure regulator have a hole in the center of it like mine? I noticed today there is an exposed hole on the top of my fuel pressure regulator. On the Sc400 its the fuel pressure regulator on the drivers side.

There is a small round area that is clean where the rest of the regulator is dirty, so I think something is missing. Also, I can smell fuel if I stick my nose near the top of the regulator. If anyone can take a quick look to see what there's looks like that would be awesome. I think i'm missing a screw that should be there.

It may be hard to see detail of the hole, but there is a hole there and further down that hole there are some threads.

INTIMAZY

iTrader: (5)

I think thats normal. You have a vacuum line already connected to it. That top "hole" may be the same thing as the "dimple" on the 1JZ FPR. Think of it as the belly button of the car

Lexus082

The only thing is down inside that hole it is too clean. Its looks like brand new shiny metal down inside that hole, you cant see it in the photo. It should be crusted with crud just like the rest of the fpr assembly. There's two fuel pressure regulators and this one in question is the same part number for the sc300's i believe. And I smell fuel coming from it which i don't believe is normal.

stockhatch

iTrader: (12)

How does the car run?

Lexus082

Its been stalling out and will restart right after but dies after a second. I picked up a replacement regulator and there is a screw and washer that is suppose to be in that hole. I'm not sure what the purpose is, like if its some relief valve of some sort. Or if its just a screw holding part of the internals of the regulator together. Does anyone know how this regulator functions?

Again, mine was missing the screw that goes down in the top center and I could smell fuel. Im hoping this is related to the stalling issues. Maybe its allowing too much fuel and flooding the engine causing it to stall or not supplying the proper pressure or amount? I have no knowledge of how this part is made or how it functions.

GamblerZ

The screw and nut on an aftermarket unit allows you to adjust and set the fuel pressure. OEM FPR is set at 41psi, but I believe the tolerance ranges allowed are 38-44psi. The OEM unit does NOT have a screw on top.

Refer to the FSM on the procedure(s) for checking your fuel pressure.

Lexus082

The fuel pressure regulator does have a screw on top, Its an oem part stamped Denso around the top along with a lexus part number. And the one I bought today from a LS400 has the same part since its the same engine and uses many of the same parts that will fit the sc400. The one on the passenger side does not have a screw on the top, its a solid metal assembly.

GamblerZ

I know on Nissans the OEM units do NOT have a screw and the aftermarket ones do. The OEM units were fixed at a prescribed psi. I would have assumed that an FPR purchased from the dealer would be the same as well. Assuming was my first mistake.

Lexus082

I appreciate you taking the time to read my post and add input, it was also my mistake to call this a fuel pressure regulator, its actually called a fuel pulsation damper. From what I have read I'm lucky it didn't cause a fire under the hood. Now I just have to hope and pray my car will be back to normal after replacing this faulty part.

Lexus082

I replaced the fuel pulsation damper but I still am having problems. The engine will start, but it shakes alot and has a really rough idle and will stall out within seconds of starting the engine. Im guessing the engine is misfiring which is causing the rough idle and stall condition. I'm just not sure what to check to try and pinpoint what the cause could be. Also, holding the accelerator will not keep the engine running. With that being the case, that kind of rules out the chance of it being a bad idle air control valve control valve right? I've been thinking and trying to solve so much now that I can't think straight anymore. Its pretty frustrating.

Lexus082

I found out that the screw is designed to rise up so I guess it some sort of valve to pulsate the fuel to the injectors. When you check for fuel pressure via Lexus shop manual it says to connect Fp and B+ on the diagnostic plug and turn the ignition on. Then your suppose to confirm the screw rises and also feel that there is pressure in the rubber section of the fuel line.

So I'm still not sure yet of the problems that would occur if that screw had completely backed its way out and fell off the fuel pulsation damper. Does anyone know what would happen in that scenario?