Removal of rear oxygen sensors info

[FLX109]

Can I remove my rear oxygen sensors without a light coming on or problems with my system if I modify my rear pipes?


FLX109

 

[BIGBADCJ]

buy o2 sensor sims

 

[C O D Y]

Yes you can. However, newer vipers need the simms (approx $75.00 part)

 

[Steve-Indy]

Thought PRE 98 did NOT need sims ???

 

[ruckdr]

Question is, all you experts can verify, PLEASE, do the rear O2 sensors do anything? I have heard, on older cars '96 included (yours FLX109), that if the rear sensors or not functioning, that a error code is set, BUT THAT they DO NOT in any way influence the fuel mixture. Don't know in what year this changed to where they do influence the mixture.

PLEASE VERIFY

Later,

 

[FLX109]

Thats what I'm talking about, IF I REMOVE MY REAR OXYGEN SENSORS ON MY 96 GTS, WILL I GET ANY TYPE OF PROBLEMS? DOES ANYONE KNOW?

FLX

 

[BIGBADCJ]

Thats what I'm talking about, IF I REMOVE MY REAR OXYGEN SENSORS ON MY 96 GTS, WILL I GET ANY TYPE OF PROBLEMS? DOES ANYONE KNOW?

FLX

just 1 hell of an annoying check engine light, just buy the sims, or the roe racing pcm, you dont want the light on all the time or you wont ever notice any other problems. if you unplug them the light comes on

 

[FLX109]

CJ
Where can I get the sims


FLX

 

[C O D Y]

Call Sean Roe.

 

[1TONY1]

Try unplugging them now and see if you get a light. If you do not get a light you can do whatever. If the check engine light comes on, then you will need the sensors connected or 02 sims. Instead of buying sims, just leave the sensors out of your modified pipes, wire tie them up and out of the way just like you would have to do sims anyway. I think as long as they are connected, even if not in the pipe, you will not get a check engine light.

 

[Steve-Indy]

FLX109...agree with calling Sean Roe...ask for tech advice extension...I think you will find that it is not necessary to have sims units to prevent "check engine" light situation on your year.

 

[BIGBADCJ]

tony if you unplug it, the light will come on. that is the case on every ob2 vehicle

 

[1TONY1]

Then he needs to leave them plugged up and tie out of the way. No different than sims......just cheaper. This won't work on later models, but a 96 will be fine.

 

[FLX109]

I will give it a try,
thanks
FLX

 

[Achilles99]

I just sold my old exhaust setup to a guy with a 97 GTS... question is, by tying the O2 sensors up and out of the way, will the fuel mixture be affected?

Can anyone verify Ruckdr's findings? Thanks!

 

[FLX109]

Will the fuel mixture be affected?

 

[1TONY1]

The rear o2's DO NOT effect a/f. They only look to see if the cats are in/working. On 1996/97/98/??? they don't even set codes with no cats.

 

[FLX109]

So, like you said in a previous post Tony, I can just keep them connected and tie them up and I won't get any lights or codes and no problems with fuel/mixture?

FLX

 

[ChicagoGTS]

If they don't throw codes on those year cars, don't they effect the drivability in closed loop (surging and bucking during normal driving)? And aren't there soft codes that don't trip the CE light. I've read all of these posts on O2 sensors and it sounds like based on what year your car is they all do different things. My car for example is probably the most confusing of the bunch since 98' is the first year sims are recommended for. I've read posts saying they're not needed and posts that say it's a must do, well I don't have sims on my 98' yet (ordered them yesterday from Jon B) and after 3000 supercharged miles I have never had an 02 CE light but I do get the bucking and the surging that is claimed to be caused by not having cats, also I did recently dyno my car and it was a hair under 12 A/F across the board so I have to agree with tony about the rears not affecting the A/F but then again 02's aren't used at WOT so are we sure that nothing is happening in closed loop I don't have the equipment to tell.

And since were on the subject of problematic O2 sensors; What is the difference between the front O2's being installed at the collector as opposed to the 3&4 primary pipes. I understand that at the collector you get a "more accurate reading" but at what cost (sluggish warm ups and erratic idle). My belanger has both **** positions and I'm really questioning whether or not I want to keep them at the collector. How well does drilling out the O2 shrouds work? This O2 stuff makes my head hurt.

 

[1TONY1]

So, like you said in a previous post Tony, I can just keep them connected and tie them up and I won't get any lights or codes and no problems with fuel/mixture?

FLX

Mine have been in and connected with no cats for many miles.....no codes. Think about it...with sims...if a/f was effected by rear o2's the pcm would see the same thing all the time which would also mess with the a/f. Call Roe and ask him.

 

[txlen]

ok...here's my finding's...on older cars they won't throw a check engine light..on late 1999 cars and up it will kick the light on..at least thats what i've found so far....jus buy the sim's from sean roe and tie them up outta the way.....Len

 

[ChicagoGTS]

What I'd like to know is without throwing a code, could the rear O2 sensors affect your cars performance in closed loop operation in anyway beyond the CEL?

 

[txlen]

i'd say no...they only monitor the catalytic convertorand see if there's a drop from front to rear....Len

 

[KenH]

What I'd like to know is without throwing a code, could the rear O2 sensors affect your cars performance in closed loop operation in anyway beyond the CEL?

My understanding is in line with what Tony said up above. The CPU uses the pre cat O2 sensors only for its closed loop control.

The post cat O2 sensors are only there to measure the efficiency of the cats themselves. The CPU expects to see a difference in the O2 reading before and after the cats from the two sets of sensors if the cats are working correctly.

On newer cars, bad readings between the sensors causes it to set a check engine light to indicate that the cats are bad. Having the check light on causes the CPU to automatically adjust the car to run richer (safe mode) which cuts down on power a bit (and therefore does have an affect).

On the older cars that do not set the light, I assume the CPU does not go into the safe mode and therefore has no affect, but I don't know that for sure.

 

[Marc Lublin]

In a 96 all you have to do is keep them connected, tie them up and put a cap on the bungs. I've heard the 96 computer is pretty stupid.

 

[FLX109]

Back to this again, I am putting a SRT10 side Race exhaust on instead of the rear pipe mod, their is no place for the rear oxygen sensors in this pipe unless I drill them out, extend wires, weld etc, I am just going to clamp everything together and hang the exhaust,Can I just keep these sensors plugged in and tie them up? I don't want to try it and have bad fuel/mixture or get a light and have to clear it, I just sent an e-mail to sean roe, still waiting for response.
Anybody?

 

[Tom F&L GoR]

The rear O2 removal (or plugged in and hanging) will cause a check engine light won't make it run richer. Think about it - the rear O2 sensor is only there to see it the cats are working; why would the OEMs then make it run richer if the cats were failing? Exhaust hydrocarbon emissions would be high enough with bad cats, running richer would only make it worse.

 

[Achilles99]

Depends on what car as to whether or not it will cause a check engine light, right? I know of 96-97 GTS cars without the light, and they are running no cats..

 

[99 R/T 10]

Depends on the year, I believe that 96-98 computers will not throw the check engine light and into safe mode, but 99 and later will. The newer computers monitor more info. For performance, I believe most like the 96 computers,easier to work with.

 

[Achilles99]

Roe's site says that 98 and up require the sims... so, I guess only
the 96-97 computers are safe...