Found this resting in the buttcrack of the Starter and Starter Solenoid. Anyone have any idea what it's for? It's very small; pic was taken on my seat with my phone very close to it. A little short of half an inch.

 

That goes on the end of the fuel rail where the line from the fuel filter is. There's a small diaphragm in that end piece and that screws in under the plastic cap.

-Amp

 

I'd have to disagree with you because the fuel rail/line bolt should have a hexagonal bolt head... well, at least mine does

 

Let's start with year/model/trim level as there are many options available on 92-00 civic/del sols and it's gonnamake a difference as to what's actually under your hood.

 

I promise you, this is where this screw goes. I just rebuilt my engine and this stupid screw fell out. Took me a little but to figure it out...


Under that plastic cap. Note: Not my car pictured.

-Amp

 

Damn if it doesn't look like he's right.

https://honda-tech.com/forums/acura-...0-gsr-2825228/

Still a good idea to post year/model/trim level on future tech related posts.

 

From literally right now, just in case you want 100% confirmation...

And yes, starting with as much information as possible will drastically help your chances of finding a problem here. I just happen to have done this recently.






A spare one I have. ha

-Amp

 

What does it do?

 

They don't look the same to me. On has outside threads, the one on the fuel rail looks like it may be female threaded:




Granted the second picture could be less clear... Hard to say.

 

I think they are the same. Also, the one that fell out could have fallen out BECAUSE the threads are messed up, which is what it looks like to me.

 

That's definitely the screw from fuel pulse damper as shown. It always wants to fall out. Usually it's held in by the plastic cap fitted over the damper.

 

Sorry for the late reply! That's exactly what it was. Vehicle is a 1997 EJ8 w/B18C. Thanks for all the responses!

 

And, what does it do?

 

There is no detail in the service manual on this piece.

If I were to guess, i would say screw threads into the diaphragm inside the pulse damper. The o-ring seals the air chamber inside the device from the outside air. Perhaps this allows variable damping characteristics.....when the damper moves only slightly, the chamber remains sealed building air pressure (making the damper stiff), but if the damper moves outward a lot, the o-ring looses it's seal and the pressure build-up is vented (theoretically making the damper softer).

I'm just guessing though.

 

It keeps an internal spring aligned.

 

 

Will this screw make a noticeable difference in the overall running of the car? My 95 dx hatch randomly started running like it was on 3 cyls, i popped the cap because i was gonna check the fuel (35 miles after filling up from 1/4 tank) and verify there was pressure. When i popped the cap something fell, after robbing my parts car i realised it was this screw. Reinstalled and started car, still running shitty, i started wiggling injectors/connections and it started running right again Within 2-3 minutes of starting the car. Was it the screw or one of the injectors? Car has about 330k, it was rainy/snowy, i pulled over to make a phone call and when i went to drive away it was like someone unhooked a plugwire while idleing...this screw is only thing i noticed "out of place"... Also i posted similar question but no replies yet on that thread which is why im here

 

95 dx hatch is my daily
Part taken from 94 ex coupe....
I feel i read somewhere that the dx doesnt have one?

 

All USDM/CDM 92-95's have that setup on the end of the fuel rail.

The 96-00 did a different fuel rail setup.

 

Ok, does the screw dramatically affect performance? Car seems to be ok, but not confident thats what the issue was

 

I would suspect it could affect how the car runs. Honda put a plastic cap over the top to help hold it in place as well as make sure it wasn't lost should it back out.

slomofo did indicate it helps keep a spring aligned. Without the screw vibration could impact said spring. I'm not exactly sure how the system operates but I don't see Honda putting a screw there if it wasn't needed.

 

Still a vague answer...not to any fault of anyone on here, im guessing thats one of those parts you just throw money at it instead of questioning it, but i like to learn as i go. At this point im sort of looking for some reassurance, so im thinking about just pulling the screw to see if i can recreate the issue then cure it again... Good idea, Bad idea?
And all help is very appreciated

 

this is what frustrates me about Honda sometimes, My 92 Si and my 92 Dx (both hatch) did NOT have this pulse damper and both were completely stock when purchased.

 

That is weird, but to be fair, I'm going purely off of what I've seen to date.

Now that you say you've seen it without, I will pay closer attention.
It could also be an area thing. I'm in Canada and maybe it had to be there for CDM but could be without in USDM?

I'm looking at my first VX tomorrow so will see if it has it.

The SI engine I have has it but I'm not 100% sure it's all original. This could be where I've been misled in my belief it's on all 92-95's.
I know it's not on the 96-00 D16Y8. I have that fuel rail to play with so I am pretty sure it won't be on the D16Y7.

 

ALL USDM '92-95 Civic's have a pulse dampener on the inlet end of the fuel rail. Now in fairness to those who have a car and BELIEVE that it is otherwise stock... the possibility exists that the fuel rail has been removed/serviced in it's life and the half-assed mechanic/owner did a poor job of replacing the original parts. In many cases, the plastic covers are not re-installed and vibration effectively dislodges the dampener screw and it APPEARS that it was never there. When the car left the factory... it was there. Twenty-four to twenty-seven years later... this may not be the case.