BMW R1150GS HEGO sensor logic

Hi All and thanks for any help you can provide.

I have a used 2000 GS and the cat has been burned since I purchased the
bike. Before I replace the cat I want to make sure the HEGO/computer is
operating correctly as that is likely the cause.

After diagnosing the original HEGO and noting the voltage signal never
went above 0.15 volts I replaced the HEGO. and it is still outputting
the same voltage. I haven't replaced the computer but it is likely
working properly.

Does anyone know what I may be missing in my diagnosis? Or what the
cause of this may be?

My tests have all been done at idle, but I would think the engine should
output a rich mix at some point, especially at startup.

Thanks, Dave

 

Hi Mark,

Thanks for your input and I will check the ibmwr site next as that is a
great idea. Turns out the first HEGO probably was ok given the
characteristics are the same as the new as old.

I have worked with HEGO's in the past and they could get coated with a
layer of glass in the initial applications (downstream being cooler),
and given the design in the GS (which is outside the main exhaust path)
I had thought this is what happened. This is likely incorrect I know
now. Actually, the HEGO (heated) was invented to prevent just this
condition so that had me really puzzled but I know better.

Good luck, Dave