Stock O2's - higher reading before or after cat??
#1
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Thread Starter
Stock O2's - higher reading before or after cat??
when reading/logging the stock O2's, which one would give you a higher reading - the sensor before the cat, or the one after it??
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
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#2
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Originally Posted by 06MonteSS
when reading/logging the stock O2's, which one would give you a higher reading - the sensor before the cat, or the one after it??
Before the cats heat up and start working, the downstream 02s will mimic the upstream 02s. This is also the case if the cats are hollowed out. This is how a an obd2 system can determine catalyst efficiency. I have some multi channel scope shots of upstream and downstream 02s together that will give you an idea of whats going on. PM me if you want or need them. I would try to figure out how to get them to you.
#3
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Thread Starter
higher - that's what I mean - LOL... I should have also had "..at WOT" in my original question...
when at WOT, which one would be reading higher, the one before the cat or the one after the cat??
I'm getting a log where one of them reads .860-.870 and the other one reads .890-.915... but I'm wondering if the log headings are reversed... cuz my AFR looks good (12.6-12.8), fuel trims zero out, etc etc, but the excel file log headings show O2 #1 at .866-.872, and O2 #2 at .890-.915.
last week, using my Predator, I upped the PE ranges to be +6% in both of them... then at WOT, the O2 #1 readings were still only at .870-.880...
The O2 #2 readings are always higher than the O2 #1... and it seems like the O2 #2 numbers are right where I want to be at...
so that's why I was asking which O2 gives the higher reading at WOT - the one before the cat, or the one after the cat?
Thanks for any and all info!!
when at WOT, which one would be reading higher, the one before the cat or the one after the cat??
I'm getting a log where one of them reads .860-.870 and the other one reads .890-.915... but I'm wondering if the log headings are reversed... cuz my AFR looks good (12.6-12.8), fuel trims zero out, etc etc, but the excel file log headings show O2 #1 at .866-.872, and O2 #2 at .890-.915.
last week, using my Predator, I upped the PE ranges to be +6% in both of them... then at WOT, the O2 #1 readings were still only at .870-.880...
The O2 #2 readings are always higher than the O2 #1... and it seems like the O2 #2 numbers are right where I want to be at...
so that's why I was asking which O2 gives the higher reading at WOT - the one before the cat, or the one after the cat?
Thanks for any and all info!!
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
Last edited by 06MonteSS; 01-25-2007 at 06:47 PM.
#4
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B1S1 and B2S1 are before cat and B1S2, B2S2 are
after. Be sure which #1/#2 you're talking about.
And then, fuggedaboudit because you can't put a
good number to a NBO2 sensor in that region of
operation. It's more about heat than mixture at
that point and you don't know the temperature.
after. Be sure which #1/#2 you're talking about.
And then, fuggedaboudit because you can't put a
good number to a NBO2 sensor in that region of
operation. It's more about heat than mixture at
that point and you don't know the temperature.
#5
10 Second Club
Even though they are the same part they have different jobs. For tuning ignore the rear 02s. They are really just catalytic converter efficiency sensors. Their job is solely to monitor catalyst efficiency. The rears won't fluctuate any where near like the front because the gases have run through the cat. They will appear way more stable and centered (400-600mv) assuming you've got a good cat. If the cats start to die they will start to read like the front 02s and trip an efficiency code.
#6
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Thread Starter
Originally Posted by jimmyblue
B1S1 and B2S1 are before cat and B1S2, B2S2 are
after. Be sure which #1/#2 you're talking about.
after. Be sure which #1/#2 you're talking about.
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
#7
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As for tuning, ignore the downstreams completely. Now when you are logging, and you see discrepancies between the UPSTEAM 02s, depending on how much, that may be an issue. As was stated above, the rear 02s do nothing but monitor catalyst efficiency . They monitor oxygen content. As far as what they should show at WOT, they should be about 700mv plus. So it is possible for the rears to be pretty close to the fronts under WOT.
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#8
Banned
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Originally Posted by 06MonteSS
yeah, I don't have 2 banks... just 1 - there's only 1 exhaust comin' out of these '06 Montes, til it splits with a y-pipe at the back for the dual ends.... with 1 O2 before the cat, and one after...
AINT THAT SOME SHIZNIT. I would think like any other OBD2 Vee engine, it would have one upstream for each bank. Damn front wheel drives!! J/K,lol
#9
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Thread Starter
Originally Posted by 2001WS6Vert
The rears won't fluctuate any where near like the front because the gases have run through the cat. They will appear way more stable and centered (400-600mv) assuming you've got a good cat.
thanks!
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
Last edited by 06MonteSS; 01-26-2007 at 10:07 AM.
#10
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Thread Starter
Originally Posted by edcmat-l1
Is that not a v6? Just looked at a wiring diag and looks like you're right. (I love ALLDATA)
AINT THAT SOME SHIZNIT. I would think like any other OBD2 Vee engine, it would have one upstream for each bank. Damn front wheel drives!! J/K,lol
AINT THAT SOME SHIZNIT. I would think like any other OBD2 Vee engine, it would have one upstream for each bank. Damn front wheel drives!! J/K,lol
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com