1jz crazy high fuel pressure, bad FPR?

[kas14slider]

Hi guys, I have a 1jz swapped s14. The other day I was driving it and the car was running just fine. I parked it and when I went to start it a half hour later I noticed that I could not hear my fuel pump turning on (walbro 255). I have a switch panel so I always let the pump prime for a second before I start the car. Then I checked and the pump fuse was blown. I replaced the fuse, switched on the pump and it started making some wierd noises and the fuel pressure was at 60psi. I checked the voltage to the pump and it was the normal steady 12v, no crazy high voltage or anything. I thought maybe somehow it was my pump so I got a new walbro 255. My pump was 5 years old so I figured even if it was not the problem, I may as well get a new one. With the new one installed I turned on the pump. It sounded fine but the fuel pressure shot up to 100psi and maxed out my gauge. So next, I figured maybe it was clogged return line. I disconnected the line from the fpr and ran a line into a water bottle. The fuel pressure was still 100psi and fuel seemed to be returning just fine out of the fpr into the bottle. So the last thing I can think of is maybe the stock FPR is stuck.

What do you guys think, is my fpr bad?

 

[toyotanos]

Seems possible, I'd pull and swap it with a known good one (or swap to a quality aftermarket unit like aeromotive)

ninja edit: Might want to make sure the gauge is working correctly as well

 

[kas14slider]

Hmm, good idea on the gauge, no idea why a gauge would randomly break but I can try to find another one to try. And I am in the process of trying to find a stock fpr. I would just get an aeromotive but I don't want to spend that money and have it not be the problem.

 

[MDCmotorsports]

Check for pinched return line....

 

[kas14slider]

I thought I ruled out the return line because I disconnected the line from the fpr (which is the earliest point of the fuel return) and ran a line from the fpr into a bottle. Fuel drained out into the bottle but I was still seeing 100psi. If there was a problem somewhere else down the line, and that was causing my issue, you would think that I would see normal pressure with the clog/pinch taken out of the equation.

 

[kas14slider]

Well I just got another gauge and still reading 100. I just thought of something though. Doesn't your fuel pressure regulator have to be seeing vacuum to control the fuel pressure? So me just turning on the fuel pump and nothing else, will the regulator still control it, because it's seeing zero vacuum. But then again I swear I have turned on just my pump and looked at the the gauge and it has always read 43psi even before the car was turned on.

 

[kas14slider]

Nevermind, dumb question. I just realize that even when you get an aftermarket fpr you set it with the vac disconnected.

 

[Beals]

yup bad FPR should of replaced it before the gauge

 

[kas14slider]

I really hope getting an fpr solves it. I just always thought that when an fpr breaks the result is very low pressure. I guess maybe if the diaphram in it gets stuck closed (or open, I always get confused exactly how it works) then maybe it would not restrict the fuel flow at all and you will see insane fuel pressure.