Was wondering if anyone could tell me if I'm thinking right. I have a scanner that shows live data and the readings of the O2 sensors. Now with bank 1 (pass. side) the readings are between .12 and .675 to .8 and change, constantly bouncing. Bank 2 (drivers side) does not bounce around, climbs to .8 and change and stays there until the EGR system opens to recycle exhaust, then it drops and then slowly climbs back up even under throttle. The rear (downstream, and there is only 1) bounces just like bank 1. With the information I seen when I looked the readings up was that Bank 1 and the downstream are fine but the bank 2 is starting to fail.

Also when the EGR system is open (going down hill not on gas) bank 1 reading is .000 (along with downstream) and bank 2 reads between .025-.050, is this because it may be going or could I still have a vacuum leak somewhere? I just replaced the EGR valve along with the inlet tube and when I finished I blew smoke into the motor and none came out, telling me that all vacuum leaks were fixed. I still get codes for bank 1 and 2 (p0171/p0174) lean, can the one bad sensor throw off the other? I got one on order from Amazon since the bosh sensor is $10-$15 cheaper then Advance and my local one stopped price matching online stores.


Also could the 2 small holes (can't see but can feel them) that I have in the muffler be a factor with less back pressure in the exhaust?

this in on a 2000 exploder 4.0 ohv

 

The B1S1 and B2S1 (Upstream), must actively switch, with no bias..
The B1S2 (downstream), post CAT, monitors the exhaust gasses for pollution purposes, and should run level at mid range....

After you replace the bad sensor, clear the codes and run the MONITOR tests (drive cycle), then recheck for any pending codes.... Philip

 

is there a tolerance they should be within each other? the reason why I'm asking is my parents car (buick) is getting the same code (below threshold for buick) and after looking at the 02 readings I'm thinking there caused from a vacuum leak the computer isn't picking up on with how low the readings go (often below .1) but I didn't pay attention to the difference between the two. I figure O2 sensors work the same no matter the make and model as motors work the same.

 

As I am not a psychic, I cannot read which code you refer to...

The separate banks will not coincide in O2 data as it depends on many factors from condition of spark to length of fuel pulse...

Most times if a code/codes relate to both banks it will point to an issue common to both banks (intake leak, dirty MAF, FPR).. Philip

 

Simple fact, O2 sensors are maintenance items, and should be replaced on a regular basis, roughly 80,000 - 100,000 miles. So if you have more miles that that, the readings are a moot point, just replace them and be done with it. Failure to do so causes clogged EGR passages, damages catalytic converters, contributes to excessive carbon build up int eh engine, harms fuel economy, etc. O2 sensors were never designed to last longer than that, but even if they were, contaminants and trace minerals found in virtually all gasoline gradually coat the sensor elements and over time adversely affects their accuracy. This is why they should be replaced as a maintenance item, rather than waiting till they obviously fail.

 

failed photo posting

 

You need to upload the photo to a web-based photo sharing site, then insert the image code/link in your e-mail.

-Rod

 

I had 2 caps on the side of my throttle body that got cracked, those were the main culprit to the lean issue, there was a hose coming off of my intake pipe that was chewed up really bad ans had a hole in it, and the vacuum line coming off of the single port on the passenger side of the throttle body had little tiny cracks in the end of it where it connects into the elbow up by the firewall. The lean codes went away and the fuel trim is a lot better