E30: black tube

[Horst Apfelthaler <Horst.Apfelthaler@xxxxxxxxxxx>]

Hi,

I'm going to do an e to i upgrade on my '85 528e engine with all parts
necessary from an '88 325i.
One thing that confuses me is a black tube (it is not the fuel filter) with
3" diameter and 10" long with 2 small 
hose connectors.
One is connected to a electrical valve and the intake manifold, the other
connector is going with a fuel hose
to the back of the car (maybe fuel tank).

What is this thing used for?


Regards

Horst from Austria

'80 323i project car
'89 320iC
'95 A4 Tdi

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