strange O2 readings
Thread Starter
8 Second Club
iTrader: (26)
Joined: Nov 2002
Posts: 2,644
Likes: 3
From: mansfield ohio
strange O2 readings I recently got a predator and was watching my O2 sensors to see if i was rich or lean. I noticed at partial throttle the #1 sensors on bank 1 and 2 would fluxuate. I was running on flat road cruise control on both sensors would be reading the same then out of the blue they would go from like 800 to 150 both banks then back up? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> WTF Is this normal. the car only has 2300 miles on it it seems to run great but the mileage isnt what ive read others getting. 22 on freeway is tops and i have 273 rear.
TECH Fanatic
Joined: Nov 2001
Posts: 1,355
Likes: 1
From: Chicago (Elgin), IL
Re: strange O2 readings </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by koolrayz:
<strong> I recently got a predator and was watching my O2 sensors to see if i was rich or lean. I noticed at partial throttle the #1 sensors on bank 1 and 2 would fluxuate. I was running on flat road cruise control on both sensors would be reading the same then out of the blue they would go from like 800 to 150 both banks then back up? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> WTF Is this normal. the car only has 2300 miles on it it seems to run great but the mileage isnt what ive read others getting. 22 on freeway is tops and i have 273 rear. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, this is normal. It is essentially "switching" trims. If you do an average of this "switching" you'll see it averages out. .450mV-.485mV is pretty much stoich (14.7:1). So that average of yours should be anywhere in that .450mV to mid .500mv's under normal conditions.
I don't know if Predator allows you to view this average, but if you have AutoTap or access to A-Tap, you can hit F7 and seen the sine wave of the S1's switching from high to low and the regression line denoting the average of the switching.
<strong> I recently got a predator and was watching my O2 sensors to see if i was rich or lean. I noticed at partial throttle the #1 sensors on bank 1 and 2 would fluxuate. I was running on flat road cruise control on both sensors would be reading the same then out of the blue they would go from like 800 to 150 both banks then back up? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> WTF Is this normal. the car only has 2300 miles on it it seems to run great but the mileage isnt what ive read others getting. 22 on freeway is tops and i have 273 rear. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, this is normal. It is essentially "switching" trims. If you do an average of this "switching" you'll see it averages out. .450mV-.485mV is pretty much stoich (14.7:1). So that average of yours should be anywhere in that .450mV to mid .500mv's under normal conditions.
I don't know if Predator allows you to view this average, but if you have AutoTap or access to A-Tap, you can hit F7 and seen the sine wave of the S1's switching from high to low and the regression line denoting the average of the switching.
Re: strange O2 readings yep....O2s are for WOT (or closed loope) and LTrims are for everything else. O2s jump all over the place. They will jump up to the 0.9**s and then back down to 0.0** and then back and forth back and forth all the time. Its when you go to WOT that they should peg at 0.89* and hold. This is supposed to be about 13.0:1 ratio which is optimal for max HP.
Chris
<small>[ March 01, 2003, 12:23 PM: Message edited by: 2001CamaroGuy ]</small>
Chris
<small>[ March 01, 2003, 12:23 PM: Message edited by: 2001CamaroGuy ]</small>
Thread Starter
8 Second Club
iTrader: (26)
Joined: Nov 2002
Posts: 2,644
Likes: 3
From: mansfield ohio
Re: strange O2 readings Thanks for all the help <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" />
Re: strange O2 readings O2s are NOT for WOT only! The pre cat O2 data is CONSTANTLY sent to the PCM so the PCM can keep the A/F at 14.7:1 by adjusting the injector pulse width. As a matter of fact at WOT the PCM goes back into OPEN LOOP and IGNORES the O2 data. This is called PE mode. The Pre Cat O2 data does normally swing above and below the nominal value of 0.450mVDC. This is how it is supposed to work. The Post Cat O2s also swing in value similar to the Pre Cat O2s, but to a much lesser degree if the Cat is working properly. If the Post Cat O2s start swinging like the Pre Cat O2s the Cat is degraded and may need replacement.
Re: strange O2 readings O2s are NOT for WOT only! The pre cat O2 data is CONSTANTLY sent to the PCM so the PCM can keep the A/F at 14.7:1 by adjusting the injector pulse width. As a matter of fact at WOT the PCM goes back into OPEN LOOP and IGNORES the O2 data. This is called PE mode. The Pre Cat O2 data does normally swing above and below the nominal value of 0.450mVDC. This is how it is supposed to work. The Post Cat O2s also swing in value similar to the Pre Cat O2s, but to a much lesser degree if the Cat is working properly. If the Post Cat O2s start swinging like the Pre Cat O2s the Cat is degraded and may need replacement.
Trending Topics
Re: strange O2 readings O2s are NOT for WOT only! The pre cat O2 data is CONSTANTLY sent to the PCM so the PCM can keep the A/F at 14.7:1 by adjusting the injector pulse width. As a matter of fact at WOT the PCM goes back into OPEN LOOP and IGNORES the O2 data. This is called PE mode. The Pre Cat O2 data does normally swing above and below the nominal value of 0.450mVDC. This is how it is supposed to work. The Post Cat O2s also swing in value similar to the Pre Cat O2s, but to a much lesser degree if the Cat is working properly. If the Post Cat O2s start swinging like the Pre Cat O2s the Cat is degraded and may need replacement.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Re: strange O2 readings sent to the PCM so the PCM can keep the A/F at 14.7:1 by adjusting the injector puO2s are NOT for WOT only! The pre cat O2 data is CONSTANTLY lse width. As a matter of fact at WOT the PCM goes back into OPEN LOOP and IGNORES the O2 data. This is called PE mode. The Pre Cat O2 data does normally swing above and below the nominal value of 0.450mVDC. This is how it is supposed to work. The Post Cat O2s also swing in value similar to the Pre Cat O2s, but to a much lesser degree if the Cat is working properly. If the Post Cat O2s start swinging like the Pre Cat O2s the Cat is degraded and may need replacement.