MC engine, catalytic converter removal

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

Checking Family Pictures, I find that the OXS sensor for the MC engine
is mounted in the front of the cat.  On the car I'm looking at, the
cat has been removed - so this begs the question of what happened to
the OXS sensor.

My bet is that the monkey lad who removed it simply chopped off the
wires from the harness and discarded the cat and sensor as one: "You
don't need an OXS sensor if you haven't got a cat."

Hmmm.  I'm assuming that the ECU is a MAC-11 (single knock sensor). And
it _does_ damn well need OXS sensor input to keep the mixture right at
cruise.  We all know the symptoms of a dead OXS sensor, and this car is
probably showing them.  No wonder he's unhappy with the performance
and wants to sell it.  Heh.

I know the car has a defective WOT switch, and I suspect a dead WGFV
as well, so I plan to change these when I pick up the car, without
even test driving it.  I'm willing to bet that pulling the codes after
I've driven it will throw up 2342, so I'm proposing to drive it back
with a MAC-12 ECU in place of the stock MAC-11.  The MAC-12 (out of the
UK MB ur-quattro) uses table-based calculations in place of an OXS
sensor and also permits 0.2 bar higher boost.

Question - when youze guyz remove the cats on MCs, what do you do about
the OXS sensor?

Oh - the turbo cooling pump is defective and has simply been bypassed.
Some people don't deserve to own these cars.

--
 Phil Payne
 UK Audi quattro Owners Club
 Phone: 0385 302803   Fax: 0870 0883933