question about test pipe and rear O2

[WolfsFang]

Last week I got my test pipe installed and i kept the O2 sensor as is. I dident disable it within my ECU nor did i do the fix. The reason why i ask this is because today a friend and I were talking about straight piping cars. He said that if the engine light comes on due to the O2 it makes the car run rich. I don't know if this is true nor do I have a A/F gauge so i dont know how rich im running but I due know iv been running lean thanks to my EGR (ordered a block off plate.) So can their be any harm done to my engine due to this or is it alright to just leave it as is?

[Chris B.]

On most cars, the rear O2 is there just to make sure the cat is working. If the check/service engine light comes on and the code for catalytic converter insufficiency pops up, it doesn't change how the engine runs.

[92awdtsi]

we installed a test pipe on my buddies 06 se and with no tuning it runs just fine.

[Erik@R/TTuning]

All depends on the car. On a Mitsu like in your profile it won't make a difference as it is only there to tell the ECU if the cat is doing it's job. But a Subaru for example does use the rear O2 feedback in fuel trim calculation.

[Ch04awd]

Doesn't matter, only the primary o2 would do that

[WolfsFang]

thanks for the info guys, i was hoping it would make me run a little rich to balance the lean from the EGR

[DPDISXR4Ti]

thanks for the info guys, i was hoping it would make me run a little rich to balance the lean from the EGR

If anything, cat-delete might make you run just a tick leaner, but you'll be running cooler, so that would offset in the big picture.

[BOOBAYS]

Yes, running test pipe will throw CEL codes and make your car run rich...
You will probably get less fuel mileage, and your exhaust will smell rich.

I don't know what kind of car you have, but toyota/lexus you can get an o2 DELETE or o2 SIMULATOR.
Using one of these will make your car run like normal with no CEL codes... Just a suggestion

[PunkboySL2]

Yes, running test pipe will throw CEL codes and make your car run rich...
You will probably get less fuel mileage, and your exhaust will smell rich.

I don't know what kind of car you have, but toyota/lexus you can get an o2 DELETE or o2 SIMULATOR.
Using one of these will make your car run like normal with no CEL codes... Just a suggestion

for OP, something like this: http://www.ebay.com/itm/304-Stainless-Steel-O2-Oxygen-Spacer-Sensor-extension-/220920465523?pt=Race_Car_Parts&vxp=mtr&hash=item336fe2c873

if you're interested.

[WolfsFang]

well when i go to remove my egr system the shop owner is going to disable my rear O2.

[JankyS13]

~my suggestion is to get a good wide band either aem or innovate lc-1 that way you can physically see if the car is running rich or lean.
~can running lean or rich harm a motor? yes and yes. running lean can burn electrodes off of spark plugs as well burn holes in pistons, running rich can cause the viscosity of oil to thin and could cause scoring on some components or wash rings depending on how rich you are running.
~some makes and models can have the rear O2 deleted with now issues, others have adverse effects and the ECU may default to dump more fuel. As the 05 cobras do when you do the rear O2 deletes.

[Chris B.]

~some makes and models can have the rear O2 deleted with now issues, others have adverse effects and the ECU may default to dump more fuel. As the 05 cobras do when you do the rear O2 deletes.

There is no such thing as an '05 Cobra.