Hello folks,

I am testing my O2 sensors in order to diagnose a soot and smog problem.
I hooked a scope to the two signal wires. At idle, it goes from about .1V to .8-.9V about once every 3 seconds. At 2-3000 rpm, it does a rich/lean cycle about 2-3 times per second.
Is that fast enough switching to not be "lazy"?

The slightly odd thing is that when I blip the throttle, it goes to .9 almost immediately, but stays there for a little bit when I let off of throttle. It doesn't drop until a little bit after the rpms fall also, but it does drop pretty fast. Sorry, I don't have the exact values for how fast it rises and falls. If it is able to do 3 rich/lean cycles per second, that means it can make at least 6 transitions per second, so that means it can do one transition in about 150 ms or less.

Does this behavior seem normal?

Car is stock 97 Integra GSR with original cat and O2.

 

It should cycle three times a second so yours sounds normal. If you pull a vacuum hose it should go lean. If you're running rich the first thing to look at is an exhaust leak.

 

If it's consistently fluctuating in response to your throttle blips, then it's probably ok. However, here is a log of a bad sensor I had. It would be ok for a few laps then go weird:

 

150ms is too long. The minimum rise time is 100ms, and most Honda O2 sensors are actually in the 50ms range.

*if you have access to a scan tool,it is much easier to diag your O2's performance.

 

u r rite. The mechanic that changed out my cat also tested the o2 with some kind of scan tool and said that it was "marginal". Time for a new sensor.

 

Save your money. Change it when it throws a code or need for smog or notice im your cars using lots of gas.

 

hey guys i just had a random question kinda has to do with this topic but i have a 93 civic dx and it runs bad once warm. it sputters real bad and has no power really. when cold it runs awesome. anyway i gutted my cat and then hooked it back up i have a feeling my 02 sensors are prolly bad. would that make my car bogg out and sputter every time i accelerate when the car is at running temp?

 

Disconnect your o2 sensor and see it it runs better. If it does you'll automatically know the o2 sensor is the problem. If not then I would look towards the ignition part such as the coil. Bad coils gives weak spark when it's hot.

 

Alright I will try that. And I have already replaced the coil pack and all that ****. Thanks a lot a appreciate the help.

 

Alright I unplugged the o2 sensor and it ran exactly the same as when it was plugged in. It still bogged out when accelerating and had hardly any power. Does the mean the o2 sensor is or isn't working properly?

 

No you wont....

 

Means the car needs further diagnosis, preferably with a scope....

 

Alright. Thanks for your help guys. About to give up and send it to a shop along with my whole god damn paycheck.

 

Dont get burned. Do a little research on the shops in your area. Look for a Honda/Acura specialist or Asian vehicle specialist if possible. Avoid the dealership unless they have a good reputation in your area.

 

Alright. Thanks man. I'll do some more research. I've been trying different things and researching and dumping money into this damn car for about 6 months now. I have no idea what to do and to damn broke to send it to a mechanic. I really like this website cause there is all kinds of nice people that help me out. Nothing seems to be working tho. I'll keep doing research and see what happens.