o2 sensors taking too long to react?

[johntomferg]

So I dropped the car off to get another COP replaced... old story - not what the post is about, etc ,etc... cost me $78 plus the cost of the COP (which I provided): to me that is a deal to free up my time to go do something else.

The mech. said that when he was running his check-over routine to make sure there was nothing else causing issues that he noticed the O2 sensors were taking too long to react. He said he was seeing about 3-5secs for them to react, and was expect fractions of a second.

Now, I am admitted not the sharpest tool in the shed when it comes to cars, but I am trying to learn when I can. Is this complete BS? Some possible truth to it? or no one else has ever heard of it or considered it?

I was always under the impression that O2 sensors fail or they work, they don't just work slow. If there is truth to it and it is working 'slow' what are the consequences of me waiting for them to fail? What is the benefit of me replacing early, etc?

Just curious, thought I would throw that out there for you guys to respond in kind.

 

[beaups]

I haven't experienced this my self but others HAVE reported this. Something to do with "cross counts" and yes they do slow down somehow. Not sure if your car has the issue, but that type of problem is NOT bs....

 

[JES_LS]

Yeah as the sensors get more buildup and age, they will begin to respond slower, plan on replacing them in the foreseeable future.

 

[LincolnTech38]

Its not uncommon as stated for sensor responce time to slow down with age, in a perfect world o2 sensors should be changed every 60k, they are a wear item.

but what I can tell you is if the responce time of the sensor drops out of spec you will get a code for the faulty sensor. Dont remember the numbers off hand but the code definition will be something along the lines of bank 1 sensor 1 or bank 2 sensor 1 slow responce.

Jay

 

[2001LS8Sport]

All correct. With age, the cross counts (the number of times the sensor reads rich to lean and back) slow down and the sensor must be replaced. Every 60K is good advice. I do mine around 50K.

It's too long to post here, but you need to understand how an O2 sensor works. It does not provide a nice steady, smooth reading of the exhaust. Instead, it will read, for example, lean and the ECM will provide extra fuel. It will then read rich, and the ECM will cut fuel. It will go lean again and the ECM will richen the fuel again...and back and forth and back and forth. Every time it does this is called a cross count. A good sensor will do this several times a SECOND! You get a nice clean exhaust and air fuel ratio this way and you think it's all a smooth control...when in fact it's tons of adjustments back and forth that average out right where they want it.

 

[johntomferg]

Thank you all for your comments back - they are very helpful.