Rear O2 tune question

[4sfed]

Okay...I've been reading all the posts regarding tune's with and without, the rear O2 sensor enabled.

My question is; why disable it in the first place? Does it hurt something to leave it enabled?

 

[4sfed]

Okay...I've been reading all the posts regarding tune's with and without, the rear O2 sensor enabled.

My question is; why disable it in the first place? Does it hurt something to leave it enabled?

I'll elaborate little.

I've seen a lot of discussion about tuners who turn them off and tuners who leave them on. Obviously, if you know how to turn them off, we're CHOOSING to turn them off. What is the purpose of turning them off? Honest question; NOT trying to start a war.

 

[bpd1151]

Turning 'em off simply eliminates the annoying CEL.

Whether you turn 'em off, or leave 'em on, the system indicates a "Not Ready" status.

Which in turn, will cause failures for those faced with emissions testing requirements.

Pretty much it, in a nutshell.

 

[4sfed]

Okay....so leaving them on triggers the CEL? Sorry.....why? I don't understand why leaving them on, triggers a code. What code does it trigger? Is removing them a workaround for a larger issue? Is something in the tune moving the system of out spec? Sorry...just trying to understand.

ROOT QUESTION: I wanna buy a tune from a tuner, and I'm trying to figure out who to invest in.

 

[SilverSH0]

Okay....so leaving them on triggers the CEL? Sorry.....why? I don't understand why leaving them on, triggers a code. What code does it trigger? Is removing them a workaround for a larger issue? Is something in the tune moving the system of out spec? Sorry...just trying to understand.

ROOT QUESTION: I wanna buy a tune from a tuner, and I'm trying to figure out who to invest in.

On a stock system, no exhaust work, you should be able to have the rear O2's on with no CEL. The front O2 sensors monitor the air/fuel ratio and are the feedback loop for the system. The rear O2's don't impact performance and simply monitor the status of the catalytic converters.

If you go with catless downpipes or sometimes high flow catted downpipes they won't be efficient enough and the stock system will throw a rear O2 CEL because the cats aren't cleaning the exhaust enough for stock. So you can either run with a CEL for rear O2's or have the tuner turn them off. Most turn them off so if the engine throws a different CEL they will know to check it.

 

[4sfed]

On a stock system, no exhaust work, you should be able to have the rear O2's on with no CEL. The front O2 sensors monitor the air/fuel ratio and are the feedback loop for the system. The rear O2's don't impact performance and simply monitor the status of the catalytic converters.

If you go with catless downpipes or sometimes high flow catted downpipes they won't be efficient enough and the stock system will throw a rear O2 CEL because the cats aren't cleaning the exhaust enough for stock. So you can either run with a CEL for rear O2's or have the tuner turn them off. Most turn them off so if the engine throws a different CEL they will know to check it.

Ah! Ok, makes sense! Thanks!


Sent from my iPhone using Tapatalk

 

[SHOdded]

Some will even go to the extent of returning downpipes to stock before the emissions test, and run the miles necessary to clear the CEL. So if you want to do that, keep the stock DPs.

 

[4sfed]

Some will even go to the extent of returning downpipes to stock before the emissions test, and run the miles necessary to clear the CEL. So if you want to do that, keep the stock DPs.

Yeah, I've read on here that some cat'd DP's don't really do the "cat" thing well. Are there aftermarket DP's that actually have fully/proper functioning cats? And if so, do they offer a performance advantage? Sorry, I know I'm kind of forking the purpose of this thread, but...one question leads to another.

 

['14SHO]

PPE high flow catted will not throw codes