Ldorris

All of the bank 1 sensors are very low, and sensor 3 isn't registering. All of bank 2 seems fine. Why would ALL of the one bank sensors have low voltage?

fyi, 2001 S600 with occasional misfires on various cylinders (most commonly 8 or 9, but never consistent... sometimes no misfires). Also smokes from tailpipe after warm and under load. I cleaned the venturi for the PVC system and changed all breather hoses. Much less smoke than previously, but still some.

kraut56

You getting any SDS codes like TWC DAMAGE (or so)? It means the engine controller cuts the fuel to the affected cylinder to prevent damage to the cat. Could after a while result in partially blocked cat (s).
Took a while to fix with new O2 sensors both upstream AND downstream, and cheating by shimming the bad reading O2s.
Eventually the cats cleaned themselves by long highway driving.
Was sticking a endo camera into the cat to see the blockage, can't find the pixes right now.
Good luck - you need SDS, otherwise you just get "misfire cyl # XX" on any other scanner.

Ldorris

I haven't had access to SDS, so i've only been using regular OBD2 scanner. It was throwing misfire codes, but since the post i sealed up a potential vacuum leak where a hose connects on top of the throttle body. Codes disappeared had vacuum come up to 19" hg, but the 02 sensor readings remained the same. Car still seems like it runs out of breath. Can only rev to 3400 rpm. I removed the upstream 02 sensors to see if that would help if the were blockage. Made no difference.
it's interesting to me that bank 2 sensor 3 is reading absolutely nothing. Half of my fuel trims are reading absolutely nothing as well.

tim687

Any updates?