Fuel Pulsation Damper (Adjusting Screw)

LaurentD

New Member
Sep 20, 2010
17
0
0
Montreal, Qc
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:
p1739910_1.jpg


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?
 

LaurentD

New Member
Sep 20, 2010
17
0
0
Montreal, Qc
hvyman;1739935 said:
Just put the screw in and tighten it.

Yeah, that's what I did. I guess it's better that way then without putting the screw back in at all?

It seems that it's just another part that I'll have to replace someday, just to be safe. I would have liked to know if the screw has a preload function to it thought...

Thanks for the answers!
 

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
12,568
1
38
Fullerton,CA
Its not even listed in the tsrm. Its sort of a common problem for them to loosen up. Its only there to soften up the oscillations in the rail. Not a super important part but no reason to delete it unless your super modified and can do without.
 
Oct 11, 2005
3,819
20
38
Thousand Oaks, CA
The FPD damps resonances in the fuel rail. Its a lot more important than people make it out to be. Without it there will be rpm ranges where the fuel delivery drops out.
 

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
1,836
0
0
Alberta
www.gyoba.com
3p141592654;1741945 said:
The FPD damps resonances in the fuel rail. Its a lot more important than people make it out to be. Without it there will be rpm ranges where the fuel delivery drops out.
This.

Toyota DID put it in there for a reason. It might be less important if we didn't have batch-fire injectors, but we do.

I imagine that it also takes some of the hit at the 9-12V switch in FP voltage, so MAYBE it's less important if you have a full-time 12V mod and aftermarket fuel pump. I'm personally not willing to make that bet with my car...
 

Crypton2006

New Member
Jun 26, 2006
294
0
0
Phoenix Az
Fpd free since 2009 and loving every minute of it.
I have a good one u can have if u pay for shipping

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