that was really good!

the third thing, if i may add it, is that they wrote the manual in Japanese and then translated it into English. so they say noise, but it might not be a literal translation. also if you've ever head the fuel system pulsate, it is really loud, if you've ever heard house plumbing do a water hammer type thing it does sound like that.

the second housekeeping item is that there are ~3 or 4 versions of the S5 T2, the Japanese, the USA, with and without the cold start assist and then the European version with its extra FPR (for reasons). so the vacuum hoses in the back of the upper intake vary a little between versions, and then the US has the AWS and the PS idle up solenoid. not sure what version the vacuum routing is, or what your version is, but its best practice to pull the hose off at both ends and make sure it goes where its supposed too!

ok the funny story, my old boss used to work for Alfa Romeo, and they wrote their manuals in Italian, and then sent them to some un-named college here, and the Italian students translated them. so every month when the new price books showed up, there was a group phone call to laugh about the butchered translations.

 

The fansubs of the second season of Initial D after Takumi blew the engine up were hilarious!

 

like springs on the suspension, if you make changes to the fueling system the damper that was previously on there may not actually be in control/tuned for where it’s needed after the changes

thousands of wankel race engines run without a MOP. There was big fuss made over on RX8Club many moons ago about Renesis engines going boom or losing compression on premix without the MOP. One racer started the whole thing claiming that, but it was directly in contrast with the long-running Mazda Pro Formula race series using the Renesis on premix.

My favorite Renesis engine vid just to add a break from all this wankel fuel system wankering-on

.

 

If you really want to be concerned about the exact fuel pressure differential across the injector, every injector would have its own regulator referenced to the intake runner where the injector is. This would also require each injector have its own pump.
what is the air pressure in the runner versus where the regulator gets its feed? Note that the primary and secondary halves of the intake manifold may also have different pressures.

To some extent, engineering follows fashion. Bearings used to have tangs to locate them, modern engines do not. The tangs are only necessary to make manual assembly faster, the bearings are held in place by crush fit. (rotary engine building tip: Grind the tangs off of rotor bearings before you press them in. They are a liability in case the e-shaft grabs the bearing and spins it, which no tang is going to stop, but a tang WILL give you negative clearance if that happens)

But in WWII aircraft engines, the bearings had locating dowels. Were the engineers morons for using these pointless devices? Of course not, but they were also working with what were currently common practices.

On the flip side, Flathead Fords had floating rod bearings. No press fit. They had clearance on both sides like a turbo bearing.

 

Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So, if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.

I had my car buck once, slowly accelerating up a slight hill. The above information about these "hot spots" answer some of my questions and make sense. I was not running a PD at the time. After reading the threads about PD's I have come to the conclusion that if you have a Turbo, it is of great benefit to have a PD (or two!) in the fuel system. If you have a N/A engine you don't really need one because it operates at a much lower power band. If my new engine starts to buck I will install a PD.

I also found out that the screw and o-ring actually move in and out of the housing as the diaphragm moves, interesting.

 

Herko Fuel Pressure Damper PR4188 for S4 N/A cars.

All metal construction for 55 bucks on amazon. . .. . . Why wouldn't you use one at that price?

This is simply a pressure drop problem. . . . . . .Fuel injectors want a known, and optimal, P1 inlet pressure and P2 outlet pressure to work at optimal performance. . . .Run outside that window and you risk delivery rates that are out of spec and/or droplet size issues.. . .The pressure dampner is there to help you stay in that window.

 

I went on eBay and as soon as I saw that there was no screw hole to leak from I purchased it for $57.77! Just have to put my finger on it a couple times a year to see if is still pulsating.

Wish you posted this sooner, a lot of back and forth for no reason. But I learned a great deal about my fuel system, thanks everyone for posting!

 

Thank you for posting this!

I think most peoples issues with the FPD is that it cost $175 from Mazda. lol

 

I received the damper and compared it to the original one I have, the untreaded area is shorter on the new one. This area supports the inlet banjo, so only half of the banjo is supported. This does not bother me, it is the same length where it screws into the rail.

What is a concern is that the special crush washer was not included!

$4.00 from Atkins.

I had a couple, so I am reusing one of them.

 

I found this photo on line.



Please replace your damper with one that can't leak fuel onto your engine!

 

Hi all, been trying to find an answer for this as I would like to replace my PD (preferably not go the delete option).

I understand that the part number is (JE27-20-180) as seen on the Atkins website.

I also see that when I google this, it brings up 929, protege etc. as seen here:

Fuel Injection Pressure Pulsation Damper Assy JE2720180 For Mazda Protege 5 RX-7 929 JE27-20-180 https://a.co/d/a9VemJc

So, having seen both of those options, and getting an idea of the general construction, wouldn't ANY pulsation damper with the same thread/dimensions work, too?

For example, one from a Toyota? Like this bad boy?
https://www.ebay.com.au/itm/36431223...mis&media=COPY

Has anyone had any experience with non-Atkins OEM (as I live in Australia, and shipping and conversion is atrocious right now) or is this really the only way (outside of the delete kit - which would open up other questions, like where to get that locally).

Any info would be appreciated.

Thanks.

 

My new PD is a

Herko Fuel Pressure Damper PR4188 for S4 N/A cars.

It is a sealed unit and if the diaphragm fails it will not leak fuel and cause a engine fire. I just have to put a finger on it and see if I still feel a pulsation going on.

 

Oh, sweet.
I did see that also and have since placed one in the EBAY cart.

Is your FC running? I take it maybe not since you haven't tested the functionality - but I guess, considering a delete kit still operates fine, it probably doesn't matter as long as it holds pressure and stops the risk.

Just trying to get the copper washers sorted, then I will pull the trigger.

I appreciate the response.

 

I posted the picture of the special washer needed for all PD's from Atkins in this thread.

My takeaway from all the posts about keeping or deleting the PD is that without the PD there will be short periods of time where the fuel pressure at the injectors will go a bit high or low and deliver the incorrect amount of fuel causing some surging at certain steady state throttle conditions. My surge happened going up a hill at about 35 mph. Always wondered what caused it.
On a highly modified engine with larger sized fuel injectors and hi flow fuel pump the spikes and ebbs are much more serious and you need all the dampening you can get, to the point where you are running two separate dampeners along with the fuel regulator!

If I am incorrect in my conclusions, someone please set me straight!

 

Yeah, thanks.
I ended up getting them from Amayama (bought 4 of each washer as they were like $1AUD) as well as the OEM PD.

As is expected, the fear of fire is in me, and any whiff of anything remotely "fuely" gives me instant anxiety.

I do also realise that I can't get a crows-foot in there to remove it and it is UIM off... which sucks to say the least.
At present, it is impossible for me to perform that work, as the car is parked on the street with no workshop/garage space in sight.

I do have a number of things I would LOVE to do whilst the UIM is off - OMP lines, EGR cleanout, maybe injector o-rings and clean... yada yada.

Bit of a shame, I have to get K's up after recent rebuild, so it is just anxious times ahead.

Thanks for replying.

 

Hi, I know what you are going through, once my engine seized I had it towed into a storage area for a few years until I found a place to live.

I found a place to work on the car next door at a cost of $100 per month, I pulled the engine out last April. Since then, I found a rebuilt engine and transmission.

I have been busy refurbishing all the parts in the engine bay, quite the undertaking! Surprised that I can still find new parts for a 35-year-old car!

Today I was able to attach the heater line to the firewall and clean a couple of the harness connectors. It is a work in progress!

If you can keep your car at the curb, (registered, insured, valid plate) you can work on the car without fear that it will be towed away.

You will need a storage area for the parts you remove.

See what you can come up with to continue your work?

 

Thanks for the inspiration and your words.
Quite challenging right now with regards to space, finances and some mental health challenges. I have all the motivation to do the work, but my tools are in storage at the moment as I am between houses.

I can do all the work, and I would love to, but my hands are tied a bit.

Your idea (and well done for doing so) of getting temporary car storage for you to perform this work is a great one. Take it slowly and get it right and your car will be awesome fun in the not too distant future :-)

Just need to be patient and pray that it doesn't burn to the ground as I slowly put K's on it enough to get it back to the rotary tech.

Perhaps I can work something out with him...

Thanks 👍🏻

 

I have purchased a NEW OEM Pulsation Damper (JE27-20-180) and would like to know (before going through the efforts in installing it) just how it should work.
Referring to the picture below - should I be getting air leaking from this area when blowing through the fuel port?
Is that where the crush washer comes in?



I just can't find any information to this effect online, and may need to create a separate post, but thought I would ask here first.