JustJeremy

So I have had my rx7(86 base n/a) for about 5 years now. Since I got the car it has ran great, the best car I have owned. I read on here a long while ago that the pulsation dampeners tend to go out. I have always worried about it, never wanted to try to replace them. Well I started smelling gas the other day. Started looking around under the hood and BINGO the little yellow cap had fuel residue all over it. So now I have the uim and the fuel rails removed.WOW everyhing under the uim is bad the vacuum lines and fuels lines all hard as a rock. Looks like it hasn't been touched in 20 years. I also broke the oil injection lines. So... I plan to do some much needed maintaince. Clean everything up remove all the oil injection and mop. I removed all the a/c components. I am going to get the fuel injectors cleaned and replace all lines and hoses. So I decided to make a thread of my project and share with everyone. I have gotten alot of useful info from the search fucntion. I will be adding photos later of my progress. If anyone has any ideas of other things to do while I am in there let me know. All help and advice would be appreciated. Thank you for looking.

AGreen

iTrader: (11)

I built my own oil injection lines a couple years ago, but I now premix. I still have the lines, and they don't leak if you just want to buy them.

Or you can build your own, there's an article in the archive about this.

Will you be replacing the pulsation damper, or will you be installing a banjo bolt?

JustJeremy

Thank you for offer for the lines but I think I am just going to eliminate the mop and run premix.
No I plan to use a banjo bolt for now.

1SWEET7

iTrader: (1)

Why use a banjo bolt? Mazda would have done that if they didn't need it I would think.

staticguitar313

iTrader: (2)

Banjo bolt works just fine some people are so superstitious i swear.

JustJeremy

I feel comfortable using a banjo bolt. I have read many threads about the pros and cons and no one has any solid proof that there is major ill effect.

3vil

iTrader: (4)

just like the sub-zero starting system right? mazda, or any manufacturer, would never put unneeded equipment on a car.

[/troll]

1SWEET7

iTrader: (1)

STFU you little newb. This has been discussed at length, and many people including myself, believe the part is there for a reason. Search, learn and STFU.

JustJeremy

I have done hours of searching on here and still there is no solid Proof. pictures or otherwise that you have to have it.Maybe I didn't find it but I will monitor the fuel system close after the overhaul.

AGreen

iTrader: (11)

^Probably the best answer yet. I as well have read and searched but never seen any evidence, first hand or on the forum, of fuel leaks developing from the lack of a PD.


Sorry to bring up the banjo bolt thing though, it obviously gets people fired up pretty quick. I'd like to see some long-term results of replacing it with a banjo. This is a great opportunity to finally put this myth to bed... or confirm its suspicions.


Let's leave that discussion for another thread, and get this one back on topic.


You have any pictures of what you're doing yet?

JustJeremy

Thanks I guess we will see what happens and how long it takes. I have some pictures but I will try to put them up later today.

jackhild59

iTrader: (7)

Pulsation dampener > Banjo bolt > engine fire

jackhild59

iTrader: (7)

Pulsation dampener > Banjo bolt > engine fire

-Jack

JustJeremy

It looks like maybe my MOP was leaking. I always wondered where I was leaking oil from.

UIM and TB removed. Vacuum lines terrible

Broken oil injector line I looked at it an it broke.

JustJeremy

Some Interesting build up on the secondary intake an throttle body. I looked and all I can findd is that it is normal. Because there is not fuel always going to the secondary. Maybe I am wrong, but if someone knows I would appreciate help.

JustJeremy

Ok so after about a year of dealing with family stuff. Trying to get a daily driver, so I can do what i want with my 7. I have com to the conclusion that the best bet for this car is to do a rebuild on the motor. there is like 200000 miles on it.So i will be making a new post for the rebuild. I have the motor almost ready to take out from the work that i have stsarted to replace the pulsation dampeners. So look out for it I will be posting it soon.

HOZZMANRX7

iTrader: (43)

Intellectually I wouldn't be without a some way to smooth the fuel delivery. Be in pulsation damper or Aeromotive fuel regulator.

BUT, from: http://injector-rehab.com/shop/fpd.html

A fuel pulsation damper is a device used to regulate the oscillation of fuel caused by the injectors opening and closing and smooth this out. Sometimes referred to as a FPD. At this time I do not have a diagram to show you, so you will need to use your imagination as I describe it the best I can. Sorry.

The damper uses a diaphragm to absorb pulses or waves in the fuel. If you could picture what would happen if you were to have a large beach ball in a pool and "bounce" the ball half under the water, let it come up and repeat several times. Waves would form. The injectors opening and closing against the pressure sent by the pump causes the same waves in your fuel system. The damper's diaphragm is used to absorb these waves and smooth the fuel delivery.

Many people say you do not need the pulsation damper, other will tell you that you do. The ones that say you do not need it more than likely either heard of someone or themselves had an engine fire due to the pulsation damper failing. The ones that say you do need it may have heard stories of an injector failing because there was no pulsation damper. The failure of the injector was caused by the fuel hammering the injector so hard that it failed. I have never personally seen an injector in this state (remember we se A LOT of injectors) and still feel this is an urban legend. If you happen to have an injector in this state, please let me know. I would LOVE to test and analyze it.

If you are running an aftermarket fuel pressure regulator, more than likely there are dampening capabilities built into the regulator. I know for a fact that Aeromotive regulator use this technology but I am not sure about others. Mounting the aftermarket regulator as close to the fuel rail as possible will eliminate any need for additional dampening. The Aeromotive units will regulate the flow by creating a stable and smooth flow.

In short, a pulsation damper does serve a purpose, but is not "nesecary". Many cars like the Mazda RX7 are equipped with a fuel pulsation damper that is prone to failing and causing an engine fire. If you plan on retaining the FPD you must keep an eye on it. Replace it BEFORE it fails or you loose your car to a fire.

fbse7en

I've done it too, no probs so far!

Rx-7fetish

Had a banjo bolt on my car when I got it in 2005 so I'm sure it was on there long before, yes the motor was dead but that was from coolant seal.
I kept the banjo when I swapped in my new motor, and have helped a few people swap to a banjo bolt as well. If your really gonna argue the case that you NEED it then think this, no fpd, possibly replace an injector, which still has never actually been proven, or keep fpd and possibly replace whole car, I can't afford all that. I would much rather sleep at night knowing I'm POSSIBLY killing an injector than killing my car, and maybe injuring myself.

JustJeremy

Thats how I feel about it. So I am going to keepp the bajo bolt mod that i started on this motor.

Twilightoptics

iTrader: (1)

Is there something wrong with the FC fuel pressure regulator? I mean it has a bit of rising rate, I've read up to 14psi. It's designed to keep the pressure regulated.

Most cars I've worked on that have come through my shop don't have a dampner. There isn't one on the GSL-SE either IIRC.

Most auto makers now are single line dead headed at the fuel rail. How does that keep a "smooth flow?" I think it's more about the pump being able to keep up with the injector opening and closing, and you're never going to hurt the injector like that. Put a fuel pressure gauge on it, can you see the pressure fluctuating more than .5psi? Didn't think so.

MazdaMike02

iTrader: (4)

Every single time the Pulsation Dampener discussion comes up it turns into Hitlers and Stalins fighting over opinions and forcing them upon others. And somebody always starts swearing at people calling them newbs. You people will never agree so just drop it. And stop trolling this guys thread. Anyway, I would take Hozzmans advice as he's a very knowledgable poster, I trust his judgement.

HOZZMANRX7

iTrader: (43)

^ Thanks for the props. But these cars are a never ending learning curve. I just share my own personal experience and what I've learned from other owners whose experience I highly respect. More over, I try not to repeat he-said/she-said which seems to happen all too often on this forum. But I'll admit I have my brain fart moments like everyone else.

I AM a big fan of over engineering. Something I suggest most posters complaining of premature failures are not. So if maintaining a Pulsation Damper, or aftermarket alternative, is over engineering then it's a good thing.

I don't know what GSL-SE's you've been seeing, but mine absolutely has a Pulsation Damper.

That said, GO SEAHAWKS!!

Twilightoptics

iTrader: (1)

Perhapse the two I have dealt with directly, allegedly in stock form, had them eliminated.