NYTooCooL

iTrader: (1)

Okay so i think my Bank 2 Sensor 2 is causing my car to drive horribly. It feels like its restricted when it drives like a air/fuel type of sluggish not just power loss in general. However I wanted to gut the precat. I know gutting the precat will give me a code, will gutting the precat mess with my 02 operating right? or do i need to get 02 sim. I don't care about just the CEL being on because i gut precat. I just want the bad 02 driveability issue gone.

rebelhell

iTrader: (1)

Somebody correct me if I'm wrong here...but I believe the secondary O2 sensors only monitor precat health. Primary O2 sensors are used to adjust A/F mixture. A clogged cat can cause those same problems and would give you a secondary O2 sensor code. You can gut your precats no problem and you will still get a secondary O2 sensor code because the car will think (correctly) that your precats aren't working. That's where O2 sims come in. They lie to the computer to make it think your catalyst is working fine.

You cannot sim your primary O2's. Those ARE required for proper A/F mix. Do you have any codes right now or are you just pulling at straws?

NmexMAX

iTrader: (22)

I have no primary O2 sensors, and only my secondaries are plugged in. Runs fine, high 22-24 for MPG's with 440's.

It can get a little erratic below 1600, but other than that, everything else is fine.

rebelhell

iTrader: (1)

Well I've heard that if the primaries fail the ecu can use the secondaries. But I don't think that's their primary function.

NmexMAX

iTrader: (22)

They are said to monitor the pre-cats and trip when not detected (as in the case of installing headers). BUT, I have long suspected that even with headers they wont trip a P0430 or what not code, because mine have not, and I've have headers since January of 2005 with this O2 same set-up.

NYTooCooL

iTrader: (1)

I have Bank 2 Sensor 2 code

NmexMAX

iTrader: (22)

Which is a secondary sensor on bank 2. So with what I said and what he said, looks as if you might have a bad cat on that bank. Or a bad sensor.

NYTooCooL

iTrader: (1)

Well im replacing the rear main cat with a test pipe and ill be gutting the front precat and replacing that sensor...hopefully that helps

MaxinO2

iTrader: (1)

rebelhell is very much correct.

Upstream/primary o2 = air/fuel ratio
Downstream/secondary o2 = cat health

I have gutted cats as well and have PO420 and PO430. I replace both my upstream O2 sensors hoping to fix my poor idle, lack of power, and a maybe straighten out a PO300 code I've had for years, which none of them went away. It did help a bit with poor idle but I'm still not satisfied and power is still lacking.

NmexMAX

iTrader: (22)

I have headers, and no secondary codes. So, do they really monitor cat health?

murphys_law

Seems like some cars throw a code and some don't. My precats are gutted and no codes, but my buddies 6 sp needed o2 sims. IDK