teke184

i was scanning my car today trying to see if i could pinpoint a misfire problem (whole nother LONG story)

and i was noticing my o2 sensor readings were different from one bank to the other.

and since my misfire problem is mostly isolated to one bank i'm wondering if that is the problem.

what exactly causes the o2 sensors to go bad? thanks

Kataklysm

I'm gonna guess its contaminants that your engine can produce or if you get some gas that isn't so great or if you are burning oil/coolant.

teke184

i think i may have an exhaust leak too....so i may replace the gaskets.

that could be throwing things off as well

unvc92camarors

i would say the carbon that eventually covers them
one reason why people replace their O2 sensors sometimes after they seafoam

NEED2SPEED

Running too much of a fuel supplement, octane booster or fuel cleaner will sometimes cause them to go bad.

Injuneer

The fact that they are reading differently may be related to the problem you are having, and not the sensors going bad. To check, swap the sensors side-to-side and see if the difference stays on the same side, or moves with the sensors.

The obvious things can contaminate the inside of the sensor.... silcon from coolant or sealants, lead in fuel, oil deposited on sensor when you installed it, excessive thread sealants or anti-sieze, etc. Carbon buildup is generally a temporary condition, and the sensors will usually self-clean when the operating conditions return to normal.

And don't forget the outside of the sensor. The sensing element is a pourous membrane, that is exposed to exhaust gas on one side, and ambient air on the other side. It is the difference in the O2 levels on the two sides of the membrane that generates the voltage. Contaminate the outside of the membrane with rust penetrant or lubricating oil, and the sensor loses accuracy. Same thing if the sensor is right next to an exhaust leak and the outside of the membrane is seeing dilute exhaust rather than ambient air.

As the sensor ages, the membrane that generates the voltage deteriorates... the response time of the sensor slows down, and the voltage level it generates goes down. When looking at the extremes of A/F mixture.... that's just about anything outside 14.6-14.8:1.... the temperature of the sensor will have a huge affect on the voltage. That's why you can't really use them to measure the rich mixtures you need for high power/torque production. If one sensor is running colder than the other, it might produce a lower voltage signal than the other, even though they were both operating at the same A/F ratio.

Smith4046

Hey Injuneer and other fine people -

Gracias to you and others who take the time/effort/consideration to input their knowledge/experience to educate others, including myself. I am amazed at the depth of some explanations afforded to viewers of this, and other F-Body sites. My hat is off, as a show of respect/thanks, to you all.

My best wishes of good luck and GOOD HEALTH to everyone.

Steve

Lunch Box

many things really - like falling in with the wrong crowd for example

97ss497

I had the same readings and my problem turned out to be a header leak.

Good Luck