Motronic 02 sensor adaptation too high

[84urq20Vt]

Guys-
I'm new to the S2Forum - been lurking as I research a project. In the meantime I have an issue with a 3B motor that is driving me crazy - and I'm having a hard time finding answers - hopefully you can throw me bone!

3B motor - exhaust smells very rich at idle - and it has been this way for almost 5 yrs and I've replaced plugs, fuel pump(Bosch stock WR/WX urq spec), swapped MAFs, TPS, injectors, new 3.0 Bar FPR, coolant sensors, etc etc. Per Measuring Blocks the 02 Adaptation has been about 175-178 where spec is 115-144. Bentley says there are 2 reasons only for high adaptation - low fuel supply and intake leaks. I've pressure tested a dozen times over the years - it's tight. New fuel pump and new FPR.

Any thoughts??

Thanks

Brandon

[quattronutter]

changed the lambda?

[dan_b]

As QuattroNutter says above, have you actually changed the o2 sensor itself (lambda) - they don't last all that long and a knackered one of those will cause all sorts of rich-running symptoms.

[84urq20Vt]

Thanks for the replies -

I put a new one on a few yrs back - it idled rich then, too, and I've swapped back and forth with the two (old and "new" (not new anymore)) Maybe I'll get another one - just hate to gamble with the $150...

But yeah I should just do it....

any other ideas?

Thanks!

Brandon

[Jamo]

Might sound daft, but have you checked the ecu?

Has it been chipped? if so try a different OEM ecu

[newsh]

check for a leak in the vac line to the ecu or inside the ecu.

[S2central.net]

MOst likely an air leak of some sort, but ...
Tried a different MAF yet ?

[84urq20Vt]

Thanks for the responses, guys. to answer a few questions - yep I've swapped with a bone-stock ECU but am going to re-visit that- have also swapped MAFs. I've pressure tested the system - no leaks. My next step is to swap in some RS2 injectors I have - see what that does....Next will be put a wideband on there and see if the tuning needs to be tweaked.

Will let you know.

Thanks for he replies!

Brandon