unidentified item

Seight-V8 · Post by **Seight-V8** » Fri Oct 23, 2009 7:21 pm

hello all,

So attached to the fuel rail on my 4.6 gems engine, is a strange valve item.

The incoming fuel goes through this item then in to the fuel rail.

It has no connectors just a round dome, with pierburg 95T342 and 7.2180.12 on it.

Anyone know what this item does, and do i need it?

So aint got any pictures, and no results from google or LR parts.

cheers

scott

CastleMGBV8 · Post by **CastleMGBV8** » Fri Oct 23, 2009 8:08 pm

Scott,

Fuel pressure regulator? Looked at my gems fuel rail and that's the only thing there, mine is Lucas it's a bit like a vacuum can for a dizzy.

Kevin.

Seight-V8 · Post by **Seight-V8** » Sat Oct 24, 2009 7:48 am

kevin,

Its on the oppesite side of the fuel rail to the fuel regulator, and has no connectors or pipes baring where the fuel goes through/

Its about 30mm in diameter and has a raised dome on the top.

Just trying to find out if i need it or not, and how important it might be.

cheers

scott

Seight-V8 · Post by **Seight-V8** » Sat Oct 24, 2009 8:51 am

Just found out its called a pulsation damper and is made by peirburg and if you type 7.21801.62.0 into google you can find it in thier 2005 catalogue.

Must be something to do with the pulses from the fuel pump.

Will see if i can fit it in somewhere.

scott

Darkspeed · Post by **Darkspeed** » Sat Oct 24, 2009 11:02 am

It will be a simple diaphram accumulator to maintain a constant fuel pressure in the fuel line from fuel pump pulses or more likely from the the injectors firing on the fuel rail.

I dont know how the fuel system works on your car but when an injector fires it could - if the fuel rail volume is not very great and there is a long distance from the pump to the rail - lower the pressure in the rail so that next injector would fire without full line pressure. The accumulator has a spring loaded diagram that provides that volume and maintains that constant pressure.

That my thinking from my hydraulics theory

Andrew

CastleMGBV8 · Post by **CastleMGBV8** » Sat Oct 24, 2009 12:18 pm

Andrew,

Interesting thoughts as to the purpose of the device, my Gems fuel rail does not have one, so am now wondering if it was introduced on a later version as an improvement to stabilise fuel pressure as you suggested.

Kevin.

Seight-V8 · Post by **Seight-V8** » Sat Oct 24, 2009 1:21 pm

there's no sign of it on the 4.6 parts diagram, and very little on google about it.

but according to pierburg should be fitted to the 3.9 & 4.6 engines.

Going to re-fit it to my fuel rail, even though i am just finishing of the change to the VEMS efi.

So must have a useful purpose.

Found alot of info on RX8 engines that have them fitted.

cheers

scott