Retaining dual O2 sensors with LTs - Chevy SS Forum
 10Likes
Reply
 
LinkBack Thread Tools
post #1 of 23 (permalink) Old 04-12-2019, 10:26 AM Thread Starter
Member
 
Avmaviator's Avatar
 
Join Date: Jan 2017
Location: Chicago Burbs
Posts: 66
Retaining dual O2 sensors with LTs

I have a set of Stainless Works LTs I will be installing soon, along with a XForce mid section, which has cats.

The SW LTs have the typical O2 bungs for the front sensors, but I'm wondering if installing the rear bungs after the cats, like the factory set up, would bring any benefits?
I have the bungs and can weld them in myself. The car will eventually get tuned.

TIA!

2015 SS SLIHM A6, roof, spare
2005 Saab 9-2x Aero, The Saabaru. Sold
Avmaviator is online now  
Sponsored Links
Advertisement
 
post #2 of 23 (permalink) Old 04-12-2019, 10:43 AM
Senior Member
 
jalanrr's Avatar
 
Join Date: Dec 2015
Location: Fayetteville, NC
Posts: 167
The downstream sensors verify the cats are working properly. They do not help engine performance.
Avmaviator and SS_Scott like this.

'16 SS, SIM, M6, spare, no sunroof; #1739, 7 of 7
'15 Suburban LT - grocery getter
jalanrr is online now  
post #3 of 23 (permalink) Old 04-12-2019, 12:00 PM
Junior Member
 
Join Date: Mar 2019
Location: round rock tx
Posts: 15
no benefit, really. the rears are just there to confirm the cats are working efficiently.
elephantrider is online now  
 
post #4 of 23 (permalink) Old 04-12-2019, 12:08 PM
Senior Member
 
Join Date: Dec 2014
Location: South Orange County, CA
Posts: 274
Are you sure about that? Many OEM's use the rear HO2S as part of fuel trim. Don't know about the LS3, specifically though. I suppose that part goes out the door when an aftermarket tune is applied, but for the OEM tune they may be doing more than just monitoring catalyst efficiency.

-------------------------------------------------------------

2015 Phantom Black MT, with sunroof, without spare

Others:
2011 Saab 9-3
2010 Suzuki Grand Vitara
2008 Suzuki B-King
1995 Mazda RX7 R2
jza80 is online now  
post #5 of 23 (permalink) Old 04-12-2019, 12:32 PM
Senior Member
 
SS_Scott's Avatar
 
Join Date: Dec 2017
Location: Commifornia
Posts: 227
Garage
Quote:
Originally Posted by jza80 View Post
Are you sure about that? Many OEM's use the rear HO2S as part of fuel trim. Don't know about the LS3, specifically though. I suppose that part goes out the door when an aftermarket tune is applied, but for the OEM tune they may be doing more than just monitoring catalyst efficiency.
Interesting, never heard that before.

It doesn't seem like it would be of much benefit. It seems to me that CATs would not be consistent enough in their behavior for downsteams to be used for fuel trim.

Sent from the butt crack of California
16 white, auto, sunroof, spare.
SS_Scott is offline  
post #6 of 23 (permalink) Old 04-12-2019, 01:34 PM
SLA
Senior Member
 
SLA's Avatar
 
Join Date: Sep 2014
Location: South Jersey
Posts: 1,025
He's talking about long term fuel trim, not short term. Some manufacturers do it. No idea if GM does.

If you don't have the post O2s installed where they belong, you will have to turn them off. They can throw a code even if used to just monitor cat efficiency.
SLA is offline  
post #7 of 23 (permalink) Old 04-12-2019, 03:23 PM Thread Starter
Member
 
Avmaviator's Avatar
 
Join Date: Jan 2017
Location: Chicago Burbs
Posts: 66
Quote:
Originally Posted by SLA View Post
He's talking about long term fuel trim, not short term. Some manufacturers do it. No idea if GM does.

If you don't have the post O2s installed where they belong, you will have to turn them off. They can throw a code even if used to just monitor cat efficiency.
My initial goal is not to have a CEL pop up for another 10-11 months till I can tune it. My warranty is up at that time, and I'd rather wait till it is expired before cracking the ECU. I'm sure people will roll their eyes at that but it is not too far away, and I can swap out the headers if something big happens in the meantime.

Thanks for everybody's input, I figured that it was probably what the second sensor did.

2015 SS SLIHM A6, roof, spare
2005 Saab 9-2x Aero, The Saabaru. Sold
Avmaviator is online now  
post #8 of 23 (permalink) Old 04-12-2019, 03:26 PM
Senior Member
 
jalanrr's Avatar
 
Join Date: Dec 2015
Location: Fayetteville, NC
Posts: 167
Quote:
Originally Posted by Avmaviator View Post
My initial goal is not to have a CEL pop up for another 10-11 months till I can tune it. My warranty is up at that time, and I'd rather wait till it is expired before cracking the ECU. I'm sure people will roll their eyes at that but it is not too far away, and I can swap out the headers if something big happens in the meantime.

Thanks for everybody's input, I figured that it was probably what the second sensor did.
It is probably going to throw a code with the longtubes and aftermarket cats...

'16 SS, SIM, M6, spare, no sunroof; #1739, 7 of 7
'15 Suburban LT - grocery getter
jalanrr is online now  
post #9 of 23 (permalink) Old 04-12-2019, 04:54 PM
Senior Member
 
Join Date: Dec 2014
Location: South Orange County, CA
Posts: 274
Quote:
Originally Posted by jalanrr View Post
It is probably going to throw a code with the longtubes and aftermarket cats...

That will likely be the case, unless the aftermarket cats are very efficient.

Here's an interesting product that might help with this particular situation, where some mods are made but without a supporting tune:
https://www.fabspeed.com/universal-9...nverters-pair/
Avmaviator likes this.

-------------------------------------------------------------

2015 Phantom Black MT, with sunroof, without spare

Others:
2011 Saab 9-3
2010 Suzuki Grand Vitara
2008 Suzuki B-King
1995 Mazda RX7 R2
jza80 is online now  
post #10 of 23 (permalink) Old 04-12-2019, 06:31 PM
Senior Member
 
jalanrr's Avatar
 
Join Date: Dec 2015
Location: Fayetteville, NC
Posts: 167
These used to be a very common (and cheap) fix for a vehicle that needed to pass an OBDII inspection when the cost of a cat exceeded the value of the vehicle.

Avmaviator likes this.

'16 SS, SIM, M6, spare, no sunroof; #1739, 7 of 7
'15 Suburban LT - grocery getter
jalanrr is online now  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevy SS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
INNOVATE Dual Lambda O2 Gauge Kit w/ (2) Bosch O2 Sensors RDP Store RDP Store 0 08-23-2017 08:36 PM
2014 SS Dyno - Kooks LTs, RotoFab & Tune Boosted Chevy SS Videos 3 09-20-2016 01:57 PM
Kooks LTs (or LTs in general) Treytaw Exhaust/Intake 5 05-08-2015 10:55 AM
Safe to use penetrating oil to remove O2 sensors? G8GT V2 Exhaust/Intake 11 11-17-2014 09:41 PM
Cadillac LTS vs Mercedes Benz S-Class \/Eight GM - News / Discussion / Opinions 1 07-26-2013 01:39 PM

Posting Rules  
You may not post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome