I read something saying that the SA will have a certain affect on the BLM. I did a zillion searches and couldn't find anything.

Does anyone know, or remember the post I'm refering to?

The jest of the post was that too much or too little timing would give inaccurate BLM's.

thanks

 

Ugh, well, yes, moving the timing can slightly fool the O2 sensor. Generally adding some timing will make things look lean, and retarding them rich. Varies by engine as to, what, slightly fools the O2 is.