Techno Duck

Edit - Please note this thread has been edited somewhat as i realized some things could be taken out of context. I am not looking to bad mouth anything, all i am interested in is information about fuel dampers so i can fix this problem. Please refrain from turning this thread into anything other than a tech post.

I am looking for feedback from people using aftermarket rails, in particular about the fuel damper used.

I have traced back some lean running issues to a defective fuel damper on my fuel rail. Damper was replaced and the problem came back after a few hundred miles. Took the damper apart and it appears the internals did not hold up long causing the original issue of 'no dampening'.

Has anyone else experienced problems or taken apart the damper after use? How did the internals look?

The problem i was experiencing was a lean spot when accelerating through the RPM range, usually around 3k rpm. I know many cars run with no dampers at all, but my car seems to be particularly sensitive to the lack of a damper. I have swapped the fuel rails probably 6 or 7 times now..so i can say with almost certainty the issue lies in the fuel rail.

I am currently running the stock rail again which i am not really happy with.. between the age of the rail (possibility of cracks) and the extra hose / fittings i am running to get the stock rail working with the fuel line setup i do not want to keep it like this for long.

I am trying to do make the last two track days of the season and would rather not run the car on the track like this.. so looking for other solutions. I have been looking at buying a Marren damper and adapting it to fit the rail i am using, though this is not easy due to the fitting differences.. (trying to adapt what i think is a -6 ORB to a 3/8NPT). I would have to run 2 adapter fittings inbetween the damper and the rail.. i would like to keep the use of fittings to a minimum so not my top choice. The other option is buying a different aftermarket fuel rail which is designed to run the Marren damper.

Appreciate useful feedback.

reno808

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zerMATT951

I'll be watching this thread. I've got my 2005-era LR fuel rail w/dampener installed now, so this could affect me too. My only issue is the tap-tap-tap-tap-tap I get from what I think is the fuel rail/dampener while running... is that a sign of a dampener not working properly? This thing sat for 5-6 years uninstalled (new) before I started using it just a couple of weeks ago.

JohnKoaWood

Jon,

Have you spoken to Chris White?

I know he is also making his own fuel rails, and can thread a damper adaptation for any damper you want to run!

Jost a thought!

rlm328

I haven't noticed any issues with my CEP fuel rail, but I am also using a Motec so tuning out a lean spot for me isn't that difficult. I am subscribed to this thread.

CDH-CTT

I just got my LR Rail kit and will be installing it this weekend.... I will check mine in about +/- 200 miles and let you know what my damper looks like....
Are you running "race fuel"??? Lean spot you are seeing it with a wideband???

Techno Duck

I just want to say i am not bad mouthing products here, just looking for technical feedback about aftermarket dampers. I have another solution i am going to try when i get home in a few weeks.

Matt, the billet rails in general are louder i have noticed. If you have no indication of a problem i wouldn't worry about it. I seem to be the only person who is having issues like this (or has noticed it), hence why it took so long to figure out.

CDH-CTT, i am running pump gas only. Nothing crazy in the fuel system either.. everything is new. Bosch HV pump, new filter, new tank screen, new Seimens 72lb injectors, tried 3 different FPR's; settled on a Fuel Lab adjustable. The lean spot can be seen on the wideband and is accompanied with a very noticeable drop in acceleration.

Carlos, what did you have to say? Feel free to PM me.

John, have not really talked to anyone else. I did consider asking Chris if he would be willing to look at the car to figure out the problem though. Trying to figure this out with the least amount of $ involved possible.. hate to buy another rail. Already dumped an absurd amount of time and money into tracing this problem down.

Mike Lindsey

CEP doesn't get his Dampers from Marren, so if theirs have problems, that doesn't mean the Marren will.
It's a copy of the Marren design but who knows where the diaphragms come from.

Marren in the past has said it's not a user serviceable part and that they should be sent in for any repairs.
So I wouldn't go opening those up for no reason. Not sure their reasons for this.

Scott H

Have you been running E85? Perhaps the rubber doesn't like ethanol (which would be a pretty stupid thing to overlook when designing a fuel damper...)

Techno Duck

Not running E85, just regular 93oct.

DDP

To think that you're having a lean spot due to no dampner, in my experience, is silly. No offense intended. I've run multiple cars, and multiple 944s (with varying injectors...stock to 83lbs) without any issues whatsoever. I would look elsewhere. What else is changing when you change the rail? Have you tried just sticking a boss AN fitting in the back of the rail? I run the CEP rail with a deleted dampner and I've installed two different rails on two different cars without issues. If I were you I would buy the 5 dollar AN fitting and plug it up. It's such a nice rail to not use and it's by far the best option out there, in my humble opinion, of course. Good luck, Duck.

fortysixandtwo

I'm using an universal fuel rail with no fuel damper. Haven't had any fueling issues with it.

CDH-CTT

The only reason to have a Fuel Dampener is to help smooth out the fuel stream for the injectors... right??? I mean my car idling I can "feel" the fuel pulses when I touch the stock rail.... I have not installed my LR rail yet....so do we think its even worth installing the Dampener on an aftermarket fuel rail???

Techno Duck

DDP, To reiterate i am aware many cars run without dampers. But the fact i have swapped fuel rails 5 or 6 (i lost count) times now with the problem never coming back while using the stock rail points towards an issue with the damper. Having replaced the defective damper, the problem was seemingly gone for about 200 miles or so, when it eventually got progressively worse. Took the damper apart and saw what is in the above pictures.. that clearly is not dampening anything. Another point towards the damper. I would really like to see what the internals look like from others using aftermarket rails.

As to what was replaced with the fuel rail? Well you answered your own question..the fuel rail. I have ruled out the pressure regulator by trying 3 different ones with the aftermarket rail.. an Aeromotive adjustable, Fuel Lab adjustable and i spent about $50 on an adapter with fittings to get the Bosch 3-bar regulator working with the aftermarket rail. I think its safe to say the regulator can be ruled out. Other than the addition of an extra foot of hose on the feed / return and a few extra fittings to adapt everything nothing else is changing.

Believe me, i want to run the fuel rail. Its a beautiful part and i agree very well made. This is why i am so adamant about getting this thing working or i would have given up 2 months ago.

Scott, i initially thought this when the problem came back; but after taking apart the damper the rubber diaphragm sealed the foam membrane off as it should have. My best guess is the foam piece did not hold up well to the heat.

CDH-CTT, check this link from Marren and make your own conclusion.

http://www.injector.com/cart/pc/view...H&idCategory=4

theedge

Could there have been a leak, letting fuel into the foam?