Air metering valve - MC-2

[isham-research.freeserve.co.uk at pop.pol.net.uk]

One of the many outstanding jobs on Puff the Magic Wagon is the
replacement of the fuel metering head.  I've had the typical symptoms
of upper O-ring failure for some time.

As always, there's a knock-on.  The CO adjusting screw in the metering
valve is so rounded out as to be useless.  I can't see that the screw
is available from Audi as a spare, and the valve itself lists at
GBP860 or so.  Quite expensive for replacing a rounded-out screw.

I have, however, a metering valve from an MB engine on the shelf.

This is where the fun starts ...

According to Audi's documentation, the MB valve is 034 133 471J.  Hmm.
I have 034 133 471M.  The valve from the MC-2 is 034 133 471L.  As far
as I can see (I've measured the bowl/cone) the only difference is
that the potentiometer on 471M has its three-pin connector parallel to
the body and the one on 471L is normal to the body.  471M is mounted
very close to the MB's inlet manifold, so it makes sense to turn it -
471L is mounted the other way round and there's plenty of room for
a straight connector.

So I'm taking the potentiometer off the 471L and putting it on the
471M - hoping this will give me a usable air metering valve.

Anyone any comments?  Source of a good adjusting screw for less than
$1200?

I'd like to resolve the 471J vs. 471M issue, too.  Audi doesn't document
a change on the MB at all - but a lot of funny things were done to the
MB engine half-way through production.  Is this one of them?  What
exactly was the change - the volumetric characteristics of the engine
didn't change?

The list seems to be down at present.  I hope it's not permanent.

-- 
 Phil Payne
 UK Audi quattro Owners Club
 Phone: 07785 302803   Fax: 07785 309674