Posted: Sat Oct 09, 2010 8:52 am Post subject: Re: Post cat o2 sensor ?
Does anyone know if the post cat o2 sensor in a 3.8l has any impact on air/fuel mix or is it just monitoring cat efficiency? Thanks.
when I did the exhaust on my Impala, I was told that it just monitored it, that the motor would not run differently, butt you would have a CEL on, and it is bright and annoying lol...unless u get a PCM and get the code deleted, or of course get a new one.
EMMJAY, your car is coming together nicely as well!
EMMJAY, you and I have always had the same taste in cars
I'm just trying to determine what role the post cat o2 plays in air/fuel mix. The reason I'm asking is that I just replaced the pre cat o2 sensor a couple of months ago. I know the pre-cat plays a big role in air/fuel mix. It had 140k with no CEL, my scan tool o2 voltages were fine and the OBD o2 test said it was okay, too. There were no codes on a dealer Tech 2 either. I replaced it anyways because i was at my wits end to figure out a very bad hesitation problem that occured when going from open loop to closed loop. Installing a new o2 solved the problem and my gas mpg went up real nice.. That being said I am now wondering if the post cat o2 should be changed to fine tune the air/fuel mix further - despite the fact it also is not showing any CEL or scan tool voltage problems. If it plays no role, i will just leave it as it is.
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