Learn time for new o2 sensors?
Thread Starter
TECH Apprentice
Joined: Feb 2004
Posts: 341
Likes: 0
From: oklahoma city
Learn time for new o2 sensors? Hopefully somebody can tell me I am just paranoid.I installed an ls6 intake and LTs about three months ago, took off the egr,air system and added true duals. Had my service engine soon lite turned off for the egr,air and rear o2.Used the front 02 in the collector until I put some miles on it.Last week, like a dumba$$, I went and put the stock program back into it from my hpp3.
Now after about 1500 miles of driving and running alittle rich but good now stalling or anything, I decided to replace the o2s with new bosch for the rear of a 2002 corvette.Never touched the business end of the o2,even though there was a very,very small amount of anti-seize(which I wiped off).Started it up and let it run for about 3 minutes and took for a drive.When I got back shut it off for about 20 minutes and started back up and it felt like it was running on 4 cyls but only for 4 or 5 seconds, did this 2x.Is there a learn process for the pcm to go thru for new o2s?Sorry about the long post.
Now after about 1500 miles of driving and running alittle rich but good now stalling or anything, I decided to replace the o2s with new bosch for the rear of a 2002 corvette.Never touched the business end of the o2,even though there was a very,very small amount of anti-seize(which I wiped off).Started it up and let it run for about 3 minutes and took for a drive.When I got back shut it off for about 20 minutes and started back up and it felt like it was running on 4 cyls but only for 4 or 5 seconds, did this 2x.Is there a learn process for the pcm to go thru for new o2s?Sorry about the long post.
No, to my knowledge there is no learn time, only a "heatup" time which only takes seconds. That's why we have heaters built into our O2 sensors. If your not getting any codes I wouldn't think the O2s are the problem, but I could be wrong.
Staging Lane
Joined: Jul 2005
Posts: 56
Likes: 0
From: usa
o2 sensors aren't typically in use for the first few seconds when you turn your car on anyways because they have to heat up. Let alone if your car is cold and you turn it on. Your o2 sensors aren't contributing ANYTHING to your car. It's until yoru car somewhat warms up it utilizes them for closed loop mode. SEeking out that 14.7:1
Thread Starter
TECH Apprentice
Joined: Feb 2004
Posts: 341
Likes: 0
From: oklahoma city
Had the egr,air and rear o2s deleted again and all seems good!No codes were set so,hopefully it was a one time thing.Been running the **** out of it and seems to run better.Thanks for the replies peeps. 
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
i'm guessing by learn time you mean... how long till your trims correct after replacing lazy O2s w/new ones...
If you reset the PCM (pull PCM fuses method or leave battery disconnected over night) it will reset your trims and they will learn from scratch.
Otherwise it may take some miles (not sure how many, I always reset mine) before they average back out (prolly 50-100 or so w/mixed driving?)
as mentioned when you first start the car up the o2s aren't used... however I believe the learned LTRIMs are ... so that could account for the stumbling ... I'd reset the PCM, and drive it around for a bit of mixed driving... it should go away... if not it will set an SES light so you'll see what it doesn't like
If you reset the PCM (pull PCM fuses method or leave battery disconnected over night) it will reset your trims and they will learn from scratch.
Otherwise it may take some miles (not sure how many, I always reset mine) before they average back out (prolly 50-100 or so w/mixed driving?)
as mentioned when you first start the car up the o2s aren't used... however I believe the learned LTRIMs are ... so that could account for the stumbling ... I'd reset the PCM, and drive it around for a bit of mixed driving... it should go away... if not it will set an SES light so you'll see what it doesn't like
