LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Off Road Pipe O2 Sensors performance?

Thread Tools
 
Search this Thread
 
Old 01-22-2013, 07:57 AM
  #1  
Teching In
Thread Starter
 
Jancorvette's Avatar
 
Join Date: Jul 2011
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Default Off Road Pipe O2 Sensors performance?

I just installed some pacesetters headers, off road Y pipe and hooker catback exhaust. For the front 02 sensors i used some extensions. For the rear 02 sensors (the one in the cats) were eliminated. I understand that this will cause my check engine light to be on, but will it affect performance?

I was under the impression that the front 02 sensors are the ones who controlled the fuel/air mix and the rear just monitored and should not affect performance. what are you guys using?
Old 01-22-2013, 08:54 AM
  #2  
9-Second Club
iTrader: (1)
 
Ed Wright's Avatar
 
Join Date: Feb 2002
Location: Tulsa, OK
Posts: 3,397
Received 8 Likes on 8 Posts

Default

The rear O2 fuel trim function needs disabled, not just the codes shut off. Amazes me how many think you just shut the codes & COT mode off. Shutting the codes off will get rid of the light.
Old 01-22-2013, 08:58 AM
  #3  
Teching In
Thread Starter
 
Jancorvette's Avatar
 
Join Date: Jul 2011
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Default

ok, two questions, do these codes affect performance? Do i need to sent out my ECM to have these codes disable?
Old 01-22-2013, 09:03 AM
  #4  
9-Second Club
iTrader: (1)
 
Ed Wright's Avatar
 
Join Date: Feb 2002
Location: Tulsa, OK
Posts: 3,397
Received 8 Likes on 8 Posts

Default

Originally Posted by Jancorvette
ok, two questions, do these codes affect performance? Do i need to sent out my ECM to have these codes disable?
Gas mileage more than performance.
Depends on how particular you are about your car.
Old 01-22-2013, 09:04 AM
  #5  
TECH Fanatic
iTrader: (10)
 
SAPPER's Avatar
 
Join Date: May 2004
Location: Halfway back on the Highway to Hell...again!
Posts: 1,572
Received 240 Likes on 170 Posts

Default

The rears do not affect performance. that only tells you that a cat is not doing it's job correctly. EPA smog garbage!!!

But it's definately something you want tuned out. If the CEL is always on, then something really does go wrong, you won't know it. Unfortunately, O2 sims are a thing of the past since everyone now just tunes out the rear O2's. They just used to plug right in and send a good signal to PCM. Now they are obsolete or very expensive if you can find them.
Old 01-22-2013, 09:08 AM
  #6  
Teching In
Thread Starter
 
Jancorvette's Avatar
 
Join Date: Jul 2011
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Default

I know i can't tuned out the rear with some handheld garbage, so do i neccessary need to sent my PCM out? Other options? HP tuners?
Old 01-22-2013, 09:28 AM
  #7  
9-Second Club
iTrader: (1)
 
Ed Wright's Avatar
 
Join Date: Feb 2002
Location: Tulsa, OK
Posts: 3,397
Received 8 Likes on 8 Posts

Default

Originally Posted by SAPPER
The rears do not affect performance. that only tells you that a cat is not doing it's job correctly. EPA smog garbage!!!

But it's definately something you want tuned out. If the CEL is always on, then something really does go wrong, you won't know it. Unfortunately, O2 sims are a thing of the past since everyone now just tunes out the rear O2's. They just used to plug right in and send a good signal to PCM. Now they are obsolete or very expensive if you can find them.
I might have information you don't? There is a binary switch in there GM says enables or disables post O2 (rear) fuel trims.
Old 01-22-2013, 12:46 PM
  #8  
TECH Fanatic
iTrader: (10)
 
SAPPER's Avatar
 
Join Date: May 2004
Location: Halfway back on the Highway to Hell...again!
Posts: 1,572
Received 240 Likes on 170 Posts

Default

Originally Posted by Ed Wright
I might have information you don't? There is a binary switch in there GM says enables or disables post O2 (rear) fuel trims.
Didn't know that. Learn something new everyday.
Old 01-22-2013, 01:14 PM
  #9  
9-Second Club
iTrader: (1)
 
Ed Wright's Avatar
 
Join Date: Feb 2002
Location: Tulsa, OK
Posts: 3,397
Received 8 Likes on 8 Posts

Default

Originally Posted by SAPPER
Didn't know that. Learn something new everyday.
Only dumb-asses don't. LOL
Old 01-22-2013, 01:50 PM
  #10  
TECH Fanatic
iTrader: (10)
 
SAPPER's Avatar
 
Join Date: May 2004
Location: Halfway back on the Highway to Hell...again!
Posts: 1,572
Received 240 Likes on 170 Posts

Default

Guess that's why you're the king of tuning??
Old 01-22-2013, 01:51 PM
  #11  
Teching In
Thread Starter
 
Jancorvette's Avatar
 
Join Date: Jul 2011
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Default

HP tuners or sent the PCM out? I lived outside the US, so shipping my PCM out is expensive.
Old 01-22-2013, 03:18 PM
  #12  
TECH Fanatic
iTrader: (10)
 
SAPPER's Avatar
 
Join Date: May 2004
Location: Halfway back on the Highway to Hell...again!
Posts: 1,572
Received 240 Likes on 170 Posts

Default

Originally Posted by Jancorvette
HP tuners or sent the PCM out? I lived outside the US, so shipping my PCM out is expensive.
In that case, you may want to look into "mail order tunes". You'll have to buy a cable and have a good, reliable laptop computer. Then you can download Tunercats, pay for it and the $EE file an download your own tunes, learn as much as you can and tweak you tunes. If you don't feel comfortable playing with the MAP, MAF, fuel trims, etc. You can download datamaster, datalog some runs/driving and email that to your tuner. Then they email a new tune back.

I used mailorder and made my own adjustments for the transmission shift points. I left the other stuff to the pros. The only thing is yours is a 97 OBDII. So there might be more to than what all I've told you. Just make sure, if you do send your PCM to someone, they don't "lock it". I had that happen by a tuner, ONCE!!! Never again!!

Last edited by SAPPER; 01-22-2013 at 03:25 PM.
Old 01-22-2013, 04:32 PM
  #13  
9-Second Club
iTrader: (1)
 
Ed Wright's Avatar
 
Join Date: Feb 2002
Location: Tulsa, OK
Posts: 3,397
Received 8 Likes on 8 Posts

Default

I never said that.
Old 01-22-2013, 05:53 PM
  #14  
9-Second Club
iTrader: (1)
 
Ed Wright's Avatar
 
Join Date: Feb 2002
Location: Tulsa, OK
Posts: 3,397
Received 8 Likes on 8 Posts

Default

Originally Posted by SAPPER
Guess that's why you're the king of tuning??
I make no claims like that.

I do, however have the actual printed listing for those (and many other) PCMs which (the OBD1 LT1, and the OBD2) fills up two loose leaf note books each, came right out of GMs back door. Everything in those two flash chips, giving the location in the binary files, the meaning, and how everything is calculated. The plug-in chips only require one notebook each.

Helps to have connections. :-)
Old 01-22-2013, 09:03 PM
  #15  
TECH Veteran
 
shbox's Avatar
 
Join Date: Dec 2008
Location: Little Rock, AR
Posts: 4,116
Received 50 Likes on 44 Posts

Default

It is probably little known or read, but it is stated in the factory manual that the rear O2s will play a limited role in fuel management if situations occur that hamper the sensors ability to monitor catalyst function. Therefore, you could likely conclude that there are some tables or switches in the PCM that correspond to that role as Ed noted.

There are probably few people that know more of what is inside that PCM than Mr. Wright.
Old 01-23-2013, 07:49 AM
  #16  
TECH Fanatic
iTrader: (10)
 
SAPPER's Avatar
 
Join Date: May 2004
Location: Halfway back on the Highway to Hell...again!
Posts: 1,572
Received 240 Likes on 170 Posts

Default

I do not doubt his knowledge and abilities. I also know he's been actively involved since the creation of the LT1. I've used just about every tuner out there since I bought the car new in 94, as well as dyno tunes. I like to experiment. WTH, it's only money and worth it for knowledge.
My list includes:
Fastchip (Ed), PCM for less, Madtuner, Street&Performance and 4 different dyno tuners. I even tried the Hyperjunk thing. Garbage!!!
This was all done during a stock motor set to the hotcam kit.
1 dyno tune was so far off, I had to trailer the car home and had to reload a previous tune. The idiot didn't even save the original tune in the car before he started. He didn't get paid and almost got a ride to the morgue.



Quick Reply: Off Road Pipe O2 Sensors performance?



All times are GMT -5. The time now is 05:35 PM.