[W126 Coupe] O2 sensor absent 1992 W126 560SEC - CIS-E

[Paul Miller]

Hello All

Thanks for imput. It was your article on adjusting mixture Dan that started
me reading up and looking further. 

My car is a UK car ( and I actually live and work in UK , temporarily
despite Australian email address )  Cats were an option up until 1992 I
think and most (? all ) UK 126's do not have them.  It looks like the lambda
sensor was only present on cars with cats ( according to a Haynes manual on
W124's in UK ) 

There appear to be three versions of the 560 according to a thread on
benzworld. 

560 called ECE with 300 hp
560 called RUF with 272 hp (pre-equipped catalyst)   ? Euro spec with cat
560 called Kat with 242 hp (catalyst)   ? USA spec

My car was built in Sindelfingen according to the chassis number tag of A
and was for the UK.  It is one of the very last W126 first registered 1992.

My owners manual gives two horsepower figures with  and without cat. 

560 SEC
nominal power 220kW ( 300HP ) at 5000 rpm
with catalyst 205kW ( 272HP ) at 5200  rpm  


The original reason I started looking was to see if I could improve my fuel
economy although I am getting EXACTLY the fuel consumption the model
brochure at the time claims.....12.7 litres / 100 km at 120 km/hr   ( I used
19.7 litres traveling 153 km at approx 120 - 130 km/hr on motorway. ) 

Seems that a lambda sensor may help the efficiency by constantly regulating
the mixture.   

I will try to get some more information from the dealer and other sources to
see if RUF version and ECE version ECU was the same.  Presumably if not, a
RUF version ECU may be the solution and then plumb in a lambda sensor. 

Other option is to apply a  test voltage ( ie simulated lambda )into the
connector for the lambda connector and measuring the duty cycle to see it
alters and hence confirming the ECU is connected to the wiring for the
lambda sensor. ( I am worried about destroying the ECU with the wrong
voltage so any advice on how to do this would be appreciated )


Regards


Paul