lsd22

Basically ls1 throwing PO134 and PO154. Have traced all wiring and no issues there. Have tested for continuity and its there. According to the scanner they just move from .45 to .44v and just alternate between that. Chasing my tail here and running out of options. O2 sensors are also brand new less then a hours run time and have tried a spare o2 and same issue is there.

Any tips or pointers? Not wanting to drive around in open loop all the time car needs to be able to do long trips economically ( as economic as an ls can)

mk3cn4

iTrader: (3)

Are you seeing this on BOTH FRONT O2 sensors? You weren't exactly clear on that. Make sure you're using the sensors on the ENGINE side of the cats.

I "believe" the rear O2 sensors (past the cats) behave the way you are describing from what I've heard, and indicate a working cat. But not sure since I don't do much with those. Not sure I personally have ever logged a rear O2 sensor to know that's what you are seeing on an LS car but worth a shot to check...

LilJayV10

iTrader: (39)

Normally when they are showing 450mv that means they are not plugged in, broken wires or failed internally.

Even in OL, the 02's will work, the PCM just ignores them.

Is this a new problem? Is the car new to you? Any recent repairs or mods?

lsd22

Appreciate the replies. Both front o2 sensors is correct and they are both before the cats. Approx 300mm from the headers. Ive had the car for years but the ls swap is recent, unsure of if this issue was present before due to not having a scanner. Wiring seems to be in perfect condition and in getting continuity from the 02 side of plug to ecu so they are definitely connected and getting a decent connection. Trying a new set of o2's tomorrow and if that doesnt fix the issue im assuming it is PCM related. No recent repairs or mods done to car either apart from replace box multiple times. Is it possible a vacuum leak could cause and issue like this?

edit; just watched the video linked and basically exactly how the o2s seem to be working just more aggressive switching rather then smooth lines.