4k Fuel Filters

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <199710211145.HAA21120@pear.epix.net> waves@epix.net writes:

> The little plastic canister you see above the metal filter isn't really a
> filter, but rather a 'holding tank'. It's exact purpose is unclear, although
> I suspect it was there for low-fuel operation, in case the fuel in the tank
> sloshes, there will always be a fuel readily available in the plastic
> cansiter.

It's a sediment trap, part # 811 501 211D.  Much debate has surrounded it in 
the past - Audi stopped fitting it to later cars (my ur-quattro didn't have 
one) although the mounting lug was still present in the underside of the 
floorpan.  It was supposedly removed by TSB because the benefit of retaining it 
did not compensate for the cost of changing it at 30000km services, although
I think stringent German regulations about working on fuel systems played a
part, too. 

I fitted one to my car over a year ago just to see what would happen - it 
currently has two fairly large ( >2mm ) pieces of rubbish swirling about in it.

If you really get bored on a wet Sunday, search the archives on "sediment 
trap".  

-- 
 Phil Payne
 Committee Member, UK Audi [ur-]quattro Owners Club