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Quick FPD Question.....

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Old Jan 1, 2006 | 11:04 AM
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Quick FPD Question.....

Is there supposed to be a hole at the top of the FPD? Mine has a hole and i think that it wasn't there before. I looked around and there was like a small piece of something that looks like it was going in that hole... i tried to get it out and i lost it.

Can I plug that hole with something else?

What is it for?
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Old Jan 1, 2006 | 11:42 AM
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Well i found a tiny screw and i screwd it in that hole. I also put some silicone around it.

What was that plug at the top for anyway? Why is it made of plastic or rubber or whatever?
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Old Jan 1, 2006 | 03:37 PM
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I'm out of town now so I can't check to see what the FPD on my car actually looks like. It sounds like you are seeing a small air vent pipe. Neither the FSM nor the parts diagram shows a separate part on top of the fuel pulsation damper, but this photo shows it:

http://www.rx7.com/store/rx7/images/...mper_small.jpg
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Old Jan 1, 2006 | 03:41 PM
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Some people actually bypass that thing by using Banzai kit. So i don't see any harm in actually pluging up that hole.
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Old Jan 1, 2006 | 03:46 PM
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There is a little rubber tab that protrudes up through the hole. I suspect it's attached to the internal rubber diaphragm that does the damping. All I know is when the diaphragm inside goes bad, it leaks and the fuel comes out that hole. Plugging the hole might be helpful in case the diaphragm leaks, but having the point of the screw in there sounds like a really bad idea.

Unless you did something to push that rubber tab back in, or cut it off, I would take it as a sign that the rubber is getting old and weak and the whole unit should be replaced. Someone with more rotary engine experience can chime in and tell me how they make that judgment call.

Dave
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Old Jan 1, 2006 | 04:02 PM
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Get a new fpd or eliminate it. A half *** repair in something like this is dangerous and can cause an engine fire.
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Old Jan 1, 2006 | 10:42 PM
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Well the way i feel about this car right now it can go ahead and burn. I'm not spending another dime on it. I'm gonna stick with the screw until it leaks or burns... either way..

Thanks for replies.
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Old Jan 2, 2006 | 07:56 AM
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I sure hope that wasn't a pointy sheet metal screw, and I sure hope your extinguisher is working well.

Dave
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Old Jan 2, 2006 | 08:08 AM
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I have a brand new FPD in my hand. There should NOT be a hole on the top of it, as others have said that is the attachment point built into the metal case for the internal parts of the dampener. IF you have a hole there, you have a problem. Why not just replace it?
It sounds like you are frustrated with your car (I can understand that!) but you REALLY don't want it to burn to the ground, do you? Because it is highly likely that you are headed that way. FPD failure is THE #1 CAUSE OF ENGINE FIRES IN 3RD GEN after all!
I guess I don't understand the logic of losing a $20K car over a $100 part.......?

Hell, if you'll pay for shipping I'll send you my old one....I'd rather do that than see another FD lost!
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Old Jan 2, 2006 | 10:36 AM
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who has actually eliminated it with no problems? It seems easy to do.
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Old Jan 2, 2006 | 11:04 AM
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So a company that spent millions of dollar in R&D with a history of nothing BUT building engines and understanding intimately the elements it takes to make something work right put these "unnecessary" FPDs in?

Makes no sense.
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Old Jan 2, 2006 | 12:37 PM
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The original FPDs are the ones with the rubber nib protruding through a hole in the top.



Dave
Attached Thumbnails Quick FPD Question.....-old_fpd.jpg  
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Old Jan 2, 2006 | 01:50 PM
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Originally Posted by bajaman
So a company that spent millions of dollar in R&D with a history of nothing BUT building engines and understanding intimately the elements it takes to make something work right put these "unnecessary" FPDs in?

Makes no sense.
I don't want to get into a debate about "if mazda put it there, it should stay there" or "if 787b had it, it makes sense" I don't ******* care about that. If they are so good in puting **** in, why couldn't they make it better then and not put crap in that fails so often.

All i'm asking if someone removed it, were there any ill affects... That's all.

With the screw in now, it seems to run fine, idle fine, and under wot nothing leaks. That's it.

As soon as i have another hour to waste on this POS i'll remove it, and i'll write back my results.
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Old Jan 2, 2006 | 01:51 PM
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Originally Posted by dgeesaman
The original FPDs are the ones with the rubber nib protruding through a hole in the top.



Dave
That nib seems to be gone, as when i looked at it, there was only a hole. What's the point of that rubber thing there anyway? All it does it falls off and starts leaking
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Old Jan 2, 2006 | 03:16 PM
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Originally Posted by bajaman
So a company that spent millions of dollar in R&D with a history of nothing BUT building engines and understanding intimately the elements it takes to make something work right put these "unnecessary" FPDs in?

Makes no sense.
You must be talking about the same company that spent millions on R&D to design a plastic AST (that fails as often as the FPD), plastic radiator endtanks , a tiny inefficient IC, a precat that cooks the rear turbo etc etc

I guess it wouldn't be a good idea to upgrade any of those, considering Mazda designed them and they must work better than anything else.


The nib is the hold the diaphram in place, once it is gone the FPD doesn't have much life left.

Last edited by BlueTII; Jan 2, 2006 at 03:20 PM.
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Old Jan 2, 2006 | 03:25 PM
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Originally Posted by BoOsTin FD
who has actually eliminated it with no problems? It seems easy to do.

I did Mine about a month and half ago.. or so.. no problems.. check out the pics..


my FPD was still good but since i had to get under there to replace the primary injectors i did the FPD.







cost me only 2.00
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Old Jan 2, 2006 | 04:00 PM
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how does it run now? do you notice anything different when it idles or wot?

Thanks
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Old Jan 2, 2006 | 04:21 PM
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Originally Posted by BlueTII
You must be talking about the same company that spent millions on R&D to design a plastic AST (that fails as often as the FPD), plastic radiator endtanks , a tiny inefficient IC, a precat that cooks the rear turbo etc etc

I guess it wouldn't be a good idea to upgrade any of those, considering Mazda designed them and they must work better than anything else.
TOTALLY different concept and parts. And to debate each point, the radiator is NOT a problem, the AST problem is wildly overstated, the precat was an emissions thing (JDM didn't have them) and the I/C is efficient and serves its purpose well (okay, at least 75% of the time). And even in the unlikely failure of a coolant related part, it is usually not as catastrophic as a fuel fire.
The point is, FPDs are used on ALL fuel injected cars that I have worked on, I just can't imagine it not having a useful purpose. Maybe it is like a human's appendix or tonsils?
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Old Jan 2, 2006 | 04:26 PM
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Originally Posted by BoOsTin FD
That nib seems to be gone, as when i looked at it, there was only a hole. What's the point of that rubber thing there anyway? All it does it falls off and starts leaking
Just curious; was yours leaking? I've never really understood what exactly happens when they fail and contribute to causing the much-feared engine fires. Usually the evidence is burned up....lol!
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Old Jan 2, 2006 | 04:29 PM
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It wasn't leaking... at least not that i can see it or smell it. I just didn't like the idea of having a hole there when there wasn't one.
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Old Jan 2, 2006 | 05:27 PM
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Originally Posted by BoOsTin FD
That nib seems to be gone, as when i looked at it, there was only a hole. What's the point of that rubber thing there anyway? All it does it falls off and starts leaking
Its not the nib thats the culprit of the leak, its the diaphram in the canister. I suspect that little rubber piece among other things slows down the leak a little in the event the diaphram breaks. If your screw isn't seated just so, your fuel may spray or atomize efficiently.

Of course you can connect your fuel lines, jump the fuel pump and check for leaks.

I'm not the fluid guy, though my brother is (and I'll ask), but as I've seen in other applications, I think the damper and regulator helps keep a steady line pressure. Yes, if you remove it gas will continue to move from A to B, but maybe with burps, hiccups and surges.

How about that comment about not dropping another dime in your car?

On the FPD, consider replacing the phillips screws with hex or allen heads.
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Old Jan 2, 2006 | 05:57 PM
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Originally Posted by danny hahn
Its not the nib thats the culprit of the leak, its the diaphram in the canister. I suspect that little rubber piece among other things slows down the leak a little in the event the diaphram breaks. If your screw isn't seated just so, your fuel may spray or atomize efficiently.

Of course you can connect your fuel lines, jump the fuel pump and check for leaks.

I'm not the fluid guy, though my brother is (and I'll ask), but as I've seen in other applications, I think the damper and regulator helps keep a steady line pressure. Yes, if you remove it gas will continue to move from A to B, but maybe with burps, hiccups and surges.

How about that comment about not dropping another dime in your car?

On the FPD, consider replacing the phillips screws with hex or allen heads.
I did pressurize the system and i shorted the fuel pump in the diagnostic box to see if there are any leaks... there weren't.
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