HAILERS

There are some pictures of a pulsation damper on the following url. You can see how it is put together. The one shown has been through a fire, and you can see where the rubber diaphram is broken, crumbled etc. Note that the screw is screwed into the metal part of the diaphram. There are not threads in the metal outer housing. That means that when the diaphram moves, the screw moves. There is a large spring b/t the diaphram and the housing. https://www.rx7club.com/forum/showth...threadid=60545 If the diaphram leaks fuel to the dry side, then it leaks out the screw opening.EDIT: It might be worth mentioning that if you put the screw back in, and screw it in until you bottom the threads out(its a shouldered screw), and keep cranking, I think that what will happen is you'll be trying to rotate the whole diaphram, which in turn means you'll eventually tear the diaphram, if you turn too much.

RETed

This was what Cutter Mazda quoted me when I asked for a 1987 Turbo II engine harness.&nbsp Yes, that's the same harness that you've described.



-Ted

RETed

You need to verify that it was the PD.&nbsp Who did the fix?


-Ted

RETed

This is the kind of thing I do NOT recommend doing.&nbsp If you click on HAILERS description in another thread, maybe you can figure out why...

Also, someone had an animated GIF on the operation of the PD.&nbsp Does anyone have the URL for that?&nbsp I was working on one for my website before I got beat to it, so I kinda gave up on it.&nbsp I think it's from Blake Q.?



-Ted

turboren

Fix? Ummm...



"future project" that I will handle when I get home (not being driven currently)

Ren

E_SURFACE

iTrader: (2)

Looks like its time to buy a fire extiguisher for me!!!
2k miles ago I install a new block, the pulsation damper was the only thing in the whole installation confused me, the screw was loose and the plastic was cracked. Still, no leaks yet! I smell my car everytime I park, call me freak, but I catch all the leaks before they go out of proportion...

I would like to thank RETed for bringing up this issue, and Mods. for archiving it.


E

ReZ311

iTrader: (4)

Hells YES!!!!!!!!!

Here is the Damage done before I redid everything!!!

CLick here to view them.

Felix Wankel

Ok I suppose I should have just left the screw dangling out, and walked to work?

My fuel smell is from injector o rings anyway.

HAILERS

After taking one apart, and seeing how it was made, I cringe a bit. Several years ago when I bought and rebuilt my first series 4, I too found the screw laying in the bottom of the plastic cap. I just screwed it back in and put the cap back on. Don't remember if I locktited the screw or not. Probably did. Just a natural response.Then nt more than a month ago I had my wifes 86 intake off trying to find out why J-rat was having problems on his car, when I saw the screw out on her car as I put the primary rail back on. I'm sure I screwed that up. I didn't wanna take the fuel hoses off to make the job easier so I just put locktite on the screw and screwed away. When it got snug, I screwed some more. Once you bottom the screw out, and keep turning, you are twisting the rubber diaphran who's bottom edges are trapped and sealed b/t two halves of the fpr body. So I question how much I damaged the diaphram. Gotta revist that car soon. Btw, once the screw is installed, it is now a part of the diaphram, meaning if the diaphram moves, the screw moves, so if you JBWELD the screw.....no movement.

Felix Wankel

I JB welded the whole thing. The edges and all, to ensure no fuel leaks out of it. Its only temporary, and I don't drive it unless I absolutely have to anyway.

ReZ311

iTrader: (4)

Hehe. I would.

HAILERS

For those too cheap for words(me), and carry a fire extinguisher in the car, you might do this. I took the intake off and then removed the PD. I took the plastic cap off and drilled a hole so a 3/16 vac tube would fit. I epoxyed the tube to the plastic cap and then epoxied the cap to the PD. Put the PD back in and ran a hose from the PD to the rear and to the left side of the transmission. That way if the PD diaphram breaks there is a path for the fuel other than collecting on top of the manifold and running down the exaust. If you do something like this, don't epoxy the PD screw or crank the screw in because you'll break the rubber diaphram.

Felix Wankel

30 miles is a long walk.

My fuel smell was a charcoal canister line that I forgot to reconnect. I saw it yesterday.

sublime529

I just replaced my PD yesterday 3/17. I would file a complaint but the signs are there for replacement. My car reaked of raw fuel, so I knew something was wrong. I did'nt drive it so nothing could go wrong, you should'nt be driving a car which smells of gas anywhere but the auto shop or your own garage. My PD which on any other car would be called a fuel regulator went up only after my car passed the 140,000 mark. I really am not upset that this happened. Its just a bitch to replace. A friend of mine who works on Toyotas said that fuel regulators go bad on those cars all of the time and way before the car hits the 140,000 mark. From what it sounds like to me, anyone who blows up there engines because of leaking fuel probably did'nt worry about the smell right away and just let it go or did not feel like paying the money involved to get it fixed because of all of the labor involved.

RETed

Mines burned down at 90,000 miles.&nbsp I've seen cars as low as 40,000 miles burn down due to leaky pulsation dampers.&nbsp I do NOT find this a regular maintenance item.&nbsp To have the potential to leak fuel all over a hot engine is no excuse - it's bad design.



-Ted

Ef-Dee

sublime529

The point I am trying to make is that on many other cars, the fuel regulators do go up and they can do the same things and damage as well. Obviously you got your REX fixed in time. Another point that I am trying to make is that it seems that the people who end up with damaged cars are the ones who sit around on getting it fixed when the sighns are there for replacement. I mean, if a fuel hose were to split and cause the same damage, would you still consider that bad design?

jbtam99

Sorry if someone else mentioned it, since I only got through the first page on this thread, but at least on the FD you can machine out the fitting and do away with the PD, My car is in Marcus William's shop right now getting a rebuild, and he does that as a pretty standard reliability modification... you'd have to ask him for details, but it makes sense that any over pressures would get routed back to the gas tank via the fuel return line. Since it seems to be one of the things FC's and FD's have in common in the engine bay, might be able to get away with it on ya'lls FC's

Just a thought and my $.02

John Metcalfe
'93 Base VR

RETed

Special thanx to Blake Qualley for creating these animated GIFs...

http://www.u-wrench.com/RE/misc/PD.html

This will explain why you don't want to JB Weld over the screw nor overtighten when putting the screw back in.&nbsp Yes, the screw is only connected to the soft diaphram...



-Ted

RETed

I might as well post em for you...

1986-1988 Zenki pulsation damper...



1989-1991 Kouki pulsation damper...





-Ted

HAILERS

That animation should give one second thought if he found the screw laying about in the plastic cap and then decided to screw the screw back in. If you screw it in and keep on a crankin after the screw bottoms out (shouldered screw), then you cause the rubber diaphram to break away and break where its trapped at its base.

Barwick

I'd be interested in getting involved, I just bought a '90 TurboII, don't know if it has FPD problems, but I want to make sure it doesn't burn to the ground.

Mr. Wankel

Let me throw my 2 cents in here. I owned a 88 GTU once with super high miles--175,000 when I bought it! It didn't take long for the flooding to begin and I ran into the usual, "crank won't start," problem. After about 3 trips to local shops, one was a Mazda dealership that said I need a new motor, a mechanic said I could disconnect the fuel pump to get the car started and then hook it back up to go. After spending a year of disconnecting the pump connection, at the rear shock tower, by hand, me and my buddy rigged a switch and it was cake to get the car started then. I'd worked in the fuel injector area before and found the PD screw loose in the plastic cap, so I put it in and continued with what I was doin. Near the end of the car's life there was always the smell of fuel but my buddy, who bought the car later, never got an engine fire. We thought the smell was due to the leaky injectors which were causing the flooding...maybe it was the PD?

Is the flooding, so common to FCs, due to the PD or the injectors? I always thought the injectors were at fault and never gave the pulsation damper a second thought...damn, I got lucky. So which is it?

Also, I was wondering about a fix to this PD problem. I guess you can't rip the bitch off and put a bolt in it's place, right? I like idea that Copandengr had about rigging a remote damper from another vehicle, but would that fix it? I know the injectors on a Rex fire a lot more than on a piston powered vehicle because of the "two-stroke nature" of the motor; could this be over taxing the diaphragm? Also, the engine compartment does get really damn hot and that could be weakening the rubber component. We need some more DIY-fix-it ideas here guys.

So the questions are:

Is FC flooding attributable to the PD or the injectors?
Can you substitute the PD with a bolt?
Is there a solution like Copandengr's that will fix this problem once and for all?
Should the PD be sprayed with that "temp insulating header spray in a can" or wraped with header tape to cut down on heat absorbtion?

7Rebel

I smelled fuel in my engine for about 6 months before it caught on fire but I didn't drive a lot during the 6 months. It had about 175,000 when it did catch on fire.

The flooding is not attributable to the PD. Flooding can be caused by a few different things... leaky injectors .... bad injector orings .... or low compression ..... some people also say that the ecu can cause flooding

You can substitute the PD with a bolt but it has to be a banjo bolt.

"Should the PD be sprayed with that "temp insulating header spray in a can" or wraped with header tape to cut down on heat absorbtion?"

That might help the PD last longer but I don't know if that would be a permanent solution .... good idea ... I never heard of someone trying that but it might work.

Is there a solution like Copandengr's that will fix this problem once and for all?

A banjo bolt should fix it once and for all.


BTW I just finished rebuilding the top half of my engine from a PD fire but haven't been able to get it started yet.


Hope I was able to help with some of your questions

George

Mr. Wankel

Seriously? If that's so, then why hasn't everyone done this by now? Why did Mazda put a pulsation damper on there in the first place if it can be completely removed?