Mystery Fuel Line/ Delivery Component

[txtorquemade]

As I was contemplating changing my fuel filter on my 87 325is 12/86 build date, I spied a very rusted "regulator" looking device in the fuel line on the engine side of the fuel filter, about 6-8 inches toward the engine.

It is rusty and nasty looking. but......

WTF is it???

Ive searched and consulted the Bently. No mention of it. I want to RR it and need to know what it is. No cam = no pics right now. Sorry.

Any help appreciated. Hoping someone just knows what this mysterious part might be.

[Jean]

PM - 13311713470
They are on realoem...when you order a replacement all you get is a 2" long plastic tube to put in it's place. It's not a filter.

[mitch500]

fuel damper i believe. i removed mine... no problems

[Mike]

early model cars have those dampers, I think my eta had 3, plus a bigger one that attatched to the outside pump, via 2" long hose. I was wondering if that could be removed as well?

[ben312]

fuel pulsation damper, it is ment to keep pressure equal in the fuel line as the injectors open. you can delete it and shouldn't have any problems.

[Lof8]

my '87 car had the fuel lines plumbed over to the passenger side of the engine bay where it circulated around an a/c line before it was routed over to the fuel rail. "fuel cooling" = retarded.

[McGyver]

my '87 car had the fuel lines plumbed over to the passenger side of the engine bay where it circulated around an a/c line before it was routed over to the fuel rail. "fuel cooling" = retarded.

possibly the dumbest idea i have ever heard of....

[Aptyp]

that was actually meant for 324td, which we never got

[ben312]

why would you want cooler fuel? cooler = more dense. well a basic N/A engine needs to keep a 14.75:1(IIRC) air:fuel mix to run. Plus doesn't more lean mean more power anyway?

[E30SPDFRK]

my '87 car had the fuel lines plumbed over to the passenger side of the engine bay where it circulated around an a/c line before it was routed over to the fuel rail. "fuel cooling" = retarded.

I've seen that before. Was a definite WTF moment

why would you want cooler fuel? cooler = more dense. well a basic N/A engine needs to keep a 14.75:1(IIRC) air:fuel mix to run. Plus doesn't more lean mean more power anyway?

You started off good...

[ben312]

I've seen that before. Was a definite WTF moment

You started off good...

well more dense fuel would throw off your air fuel mix, and runnning rich on an N/A engine causes a loss in power, so explain why a rich mix would be wanted. in a diesel engine, or a engine that ignites using compression then running a higher fuel:air mix makes sense, but in a gas engine it seems like a waste of fuel. anyone who has ever ran anything N/A with a carb knows that leaning your mix = power, so why rich up the mix?

[Adrian_Visser]

Umm yeah sorry but leaning out the mixture will not give you more power not on an injected engine. Detonation yes, higher engine temps yes, more power no. Cold fuel may be more dense but it doesn't vaporize nearly as well so with the same amount of fuel (by weight) you would get a less combustible charge, This is why you have a choke on your carburetor and why there is a cold start enrichment cycle on electronic fuel injection systems.

[nando]

N/A engines at full load typically run between 13-14:1, not 14.7:1. technically he's right though, you can make more power at "leaner" mixtures (like 14:1) but typically at the expense of engine life and reliability.

[ben312]

N/A engines at full load typically run between 13-14:1, not 14.7:1. technically he's right though, you can make more power at "leaner" mixtures (like 14:1) but typically at the expense of engine life and reliability.

I have always been told 14.7:1, the same amount of pressure at sea level(14.7psi), but as you get into higher altitude you lose pressure and thus lose your "perfect" mix. thats why the car has an O2 sensor, to adjust the mix, but you already knew that. This is why for every 1000ft in altitude you go up your car will lose ~3%hp.

A mixture is the working point that modern engine management systems employing fuel injection attempt to achieve in light load cruise situations. For gasoline fuel, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than 14.7 to 1 is a lean mixture

[nando]

14.7:1 is ideal for the most efficient burn, yes, but not neccesarily for the best fuel economy or power.

also the O2 sensor doesn't adjust fuel for altitude, the air metering device (AFM, MAF, whatever you're using) does that automatically.