Hello,
I was fixing a leak at my FPD yesterday, and putting in new gaskets when I noticed that the little screw on top of the FPD had gotten loose and was simply sitting inside the cap. I have read quite a bit about it and it seems to be a common problem, but haven't found an answer. I know that this little screw is set at the factory to the proper setting and should not be played with. However what do they set it for at the factory. Is it simply set so that it will act as a fuel pressure quick check? Or does that actually set the FPD opening pressure (info brought by CRE in this thread)? I am questioning the later affirmation, mostly when looking at this picture:
It seems that the spring would be responsible for dictating the FPD opening pressure. The only thing that I can conceive is that if you over-tighten the screw, it would pre-charge the spring, thus varying the opening pressure.
In the end, I just wouldn't mind if the fuel pressure quick check would not be available to me anymore. But I do would mind if the FPD isn't dampening the injectors pulsations correctly. I know this device is no crucial to the fuel system, but I am strong believer that Toyota engineers have put it there for a reason, and therefore I prefer a properly functioning FPD.
So what's this screw's real function?
I was fixing a leak at my FPD yesterday, and putting in new gaskets when I noticed that the little screw on top of the FPD had gotten loose and was simply sitting inside the cap. I have read quite a bit about it and it seems to be a common problem, but haven't found an answer. I know that this little screw is set at the factory to the proper setting and should not be played with. However what do they set it for at the factory. Is it simply set so that it will act as a fuel pressure quick check? Or does that actually set the FPD opening pressure (info brought by CRE in this thread)? I am questioning the later affirmation, mostly when looking at this picture:

It seems that the spring would be responsible for dictating the FPD opening pressure. The only thing that I can conceive is that if you over-tighten the screw, it would pre-charge the spring, thus varying the opening pressure.
In the end, I just wouldn't mind if the fuel pressure quick check would not be available to me anymore. But I do would mind if the FPD isn't dampening the injectors pulsations correctly. I know this device is no crucial to the fuel system, but I am strong believer that Toyota engineers have put it there for a reason, and therefore I prefer a properly functioning FPD.
So what's this screw's real function?