Two O2 probes, one pre, one post cat???

[Rob O]

OBD2 senses EGO before and after the cat to see if the cat is still
working. If they get the same reading, it makes the ECU unhappy. Best
bet is to plug the hole and zip-tie the 2nd O2 sensor to the body
somewhere so it always gets a nice fresh air reading

Rob_O

Chris wrote:
> 
> Can I throw a question into the arena please? A lot of Japanese cars
> (and others) are now appearing with 2 O2 sensors, one conventionally
> placed one pre the cat, and a second one just after the cat. if one
> removes the cat to remove back pressure on a turbo'd car as a
> performance hike what would the ECU make of this? On some cars I have
> done this to there is never a closed loop mixture problem, nor a check
> engine light either and no fault codes get stored (Toyota). I always
> replace the second probe in a similar location after the now removed
> cat(s). Thanks
> 
> --
> Best regards,
>            Chris
> 
> ----------------------------------------------------------------------------
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org