O2's all over the place??

[nybuickant]

Alright guys I need your help. I put in a scanmaster yesterday and my O2's are all over the place. They were jumping from 500's to 600's to 700's then to 100's 200's and 300's. Is this normal? It seemed to jump less when under load. Are the low numbers normal when at idle? I had no knock at anytime aven at 13lbs. boost, so I'm not that worried or should I be? Thanks guys.

 

[BoostedBug]

I may be wrong but I think i am right on this...


At Idle the car is constant from rich to lean and thus the o2's are up and down.

I think it is normal as long as it doesn't jump out of the 800's..Then it would be way to rich.

 

[Ormand]

"Bounce" in O2 Readings

Whenever the engine is in closed loop, at idle, under light load, or at cruise, the ECM will cycle the mixture from rich to lean to rich, etc. The readings will vary, back and fourth, and that's the way they should work. If they vary too slowly, that's bad. My old Turbolink manual says the O2 crosscounts should be 15 to 40 counts per frame, if the sensor is good. At wide open throttle, TPS bigger than some magic value, the ECM goes to open loop, and the O2 should NOT drop below about 700.