RE: WOT switch

[Aleksander Mierzwa <alex@matrix.com.pl>]

Audi fits various emission control devices to the cars depending on the
market they're designed for. Vehicles without oxygen sensor and
catalytic converter are imported into countries where unleaded fuel is
not available or where the emissions limits are liberal enough not to
require catalytic converter. I guess that the Audi tech you spoke to
meant that the lambda sensor was never installed on South African
models. Importing the cars with oxygen sensor and then removing it would
be idiotic. Besides, when the car with catalytic converter is run on
leaded fuel, the cat soon goes south and can get clogged with deposits.
I also don't quite understand how the fuel injection was replaced with
the one from the non-turbo cars. All 10V turbocharged and early
non-turbo cars, regardless of the emissions control devices installed,
use the K-Jetronic injection system, which is purely mechanical system. 
Turbocharged cars feature computer, which controls ingition, boost and
can also control mixture by "fooling" the fuel distributor by means of
the frequency valve. As Phil observed, depending on the country of
destination the ECU either monitors the oxygen sensor to estimate the
correct mixture or uses values stored in the memory. Some early models
did not have the frequency valve at all, so the ECU's control over
mixture was somewhat limited.
Non-turbocharged K-Jetronic cars did not have any electronic control
devices at all or, in case of US cars that required emissions control
since early 80s, had a small electronic box that triggered the frequency
valve depending on the signal from the oxygen sensor.
Later non-turbo cars got the new KE-Jetronic system. It features an ECU,
fuel metering plate potentiometer and integrated solenoid to control the
operation of the fuel distributor, so it works more like an EFI. I doubt
if any turbocharged Audis ever had this system installed, though.

Aleksander Mierzwa
Warsaw, Poland
mailto:alex@matrix.com.pl
87 Audi 5000CS turbo (mine)
88 Renault Medallion wagon (mom's)
91 mountain bike (just in case both cars broke at the same time :-)

> -----Original Message-----
> From:	Gerard [SMTP:gerard@poboxes.com]
> Sent:	Wednesday, December 03, 1997 3:36 PM
> To:	Aleksander Mierzwa
> Cc:	Quattro List
> Subject:	Re: WOT switch
> 
> > I can't believe the lambda sensor was actually removed. What's the
> point
> > of doing this? Besides, if you remove the lambda sensor from the car
> > you'll get error code 2342.
> 
> I got a call from VW/Audi about 1.5 months back. I was chatting to
> the guy about fitting EFI (yes, it was one of my darker stages in
> life) and we spoke about how different the local was from the
> international. On these cars they replaced the K-Jet on the Turbo
> models with the K-Jet found on the normally aspirated motors. He
> told me the lambda was removed and the injection changed to the
> normally aspirated 'cos  this country was (is) so backwards that
> we didn't have unleaded back in '90. I don't understand why they'd
> remove it, they could just as well have fitted one for leaded
> fuel (I understand such things exist). I am going on lambda
> removal from someone who works at the VW/Audi factory here.
> [...] 
> Thanks.
> 
> G.
> -- 
> "a thousand miles from here, there is another person smiling"
> 1990 Turbo (200T)
> name   : gerard van vught
> tel    : +27-57-912 2658 (w) / 082 923 9609 (cell)
> url    : http://www.acenet.co.za/homepages/gerard/
> e-mail : gerard@poboxes.com  / han.solo@galaxycorp.com
>          gerard@acenet.co.za / van_vught@frg.issi.co.za
> 
>