Fuel Pulsation Dampener

[Spun MkIII]

And yes, they can go bad. There is a screw in there that can work its way loose. You aren't supposed to actually do anything with it, no adjustments, etc.

I always suspected there was supposed to be a screw in that thing. Mine must have loosened all the way out a long time ago.
So, if that screw adjusts it, I would naturally assume that mine is about as far out of adjustment as possible. What negative effects might this be causing? (as compared to having no FPD at all, as previously discussed)

 

[jetjock]

Spun my man, there isn't any adjustment on it that I know of. I'm not sure what screw Nick is talking about unless its the little bolt in the top that stands proud when fuel pressure is present. That's not adjustable though, it just goes through a hole and rides in a washer that's sandwiched between two coils of the spring. Then again I didn't know fuel flowed through it so take what I say with a grain of salt

 

[Nick M]

Perhaps some do, some dont.

 

[supra90turbo]

The "adjustment screw" in the middle of mine had stripped and was always just floating around under the little army helmet there...

Always wondered what that screw was for.

 

[3p141592654]

There is an old thread on supraforums where Dean Marcum offers some insight on the FPD. I have the Cole's notes below, or you can follow the link yourself

http://www.supraforums.com/forum/showthread.php?t=249037

Here's the summary....

The screw is there to pre-load the dampner spring. Easiest way to improve flow, marginally, is to run the banjo bolt from a non-turbo 7M (the N/A motor does not have a dampner).

I have never seen a "proper way" to set the screw. However, after cutting one of the dampners open, if you have the screw all the way in it does restrict fuel flow into the rail (not a good thing).

When you did the autopsy on the dampener you had. Did it look like you could do any damage to the unit if the screw was fully installed. My aim is to count the number of turn in to full, then back out by 50% and try there for a few days.

No damage to the unit. It just limits the amount of travel of the internal "plate" against the spring. Kind of like a fuel pressure regulator backwards.

The dampner should never leak--with or without the screw in place. If it leaks then it is damaged and should be replaced. There should be no damage by replacing the screw.

 

[IHI-RHC7]

What about retaining the FPD and just drilling holes in the threaded shaft to feed the rail before the dampner. That way it still functions as a dampner but no longer restricts fuel flow.

-thank you-

 

[lagged]

dont think ours can work that way. since fuel must go through the damper before it enters the rail, youll probaby end up with a fuel leak if you just have the damper screwed into the rail.

 

[IHI-RHC7]

No, just modify the FPD so that the shank acts as a typical banjo bolt with the FPD up top. It would still function as an accumulator, just not a restriction...

 

[lagged]

No, just modify the FPD so that the shank acts as a typical banjo bolt with the FPD up top. It would still function as an accumulator, just not a restriction...

and then you must ask your self, was it worth all this trouble?

 

[IHI-RHC7]

well, if it does it's purpose, protecting the injectors and pump, and is not a restriction, thereby allowing over 500 whp...
Was it worth chucking it in a vise and drilling a standart 1/4 hole in it taking 10 min of my time?

Yes.

 

[lagged]

well, if it does it's purpose, protecting the injectors and pump, and is not a restriction, thereby allowing over 500 whp...
Was it worth chucking it in a vise and drilling a standart 1/4 hole in it taking 10 min of my time?

Yes.

then i guess the answer would be 'yes'. :icon_razz