Ok just want to make sure, but is the o2 sensor that is closest to the cat good for anything other than the cat? reason i ask is....

I have no cat at the moment, but I have a 02 simulator installed. I really need the bung for my wideband gauge to do a rough tune with the apexi before I take it to the dyno. Can I remove the lower o2 sensor & install my wideband o2 sensor into that bung with no ill-effects or does this sensor do more than just trip the CEL if your cat goes bad. I know the top o2 sensor analysis the air/fuel ratios, but wasnt sure if the bottom one did much more than the CEL for the cat.

Thanks!

 

The downstream O2 sensor is used primmarily to gauge catalyst efficiency. An O2 sim does a decent job of 'fooling' the system. I am not absolutely sure if the fuel trim gets affected if this signal is gone, but I have a feeling it's just going to nag you with the light and a code.

 

trickle,
what does the Alta down pipe come with? Are there any preinstalled bungs? and if you were to install teh wideband, can you use that to plug in the to the mini's basic narrow-band sensor as well? or would you need to install another...

 

my advice: add a cat, add another bung for the wideband; tune away while not stinking up the world behind you.

 

The Alta DP has 2 bungs welded into it. The wideband gauge I have has its own calibrated o2 sensor. I just need it to do a rough tune asap, I dont have time to weld in another bung at the moment not to mention I am not sure you can weld in a steel bung to stainless steel.

I will be installing a cat, just not yet. This car is not a daily driver, so I am not overly concerned. I want to get readings with/out the cat, then when I go back and install the cat, compare the numbers....

Great bear, if I take the stock o2 sensor out but leave it connected just tucked up under the car, does the o2 sim fool even if it still doesnt see anything? This is just for temp testing, it wont be left this way. I just want to be able to do a rough tune via the wideband in order to drive the car to the dyno.

 

Update:
I pulled the stock o2 sensor, the one with the simulator hooked to it & mounted it up above the heat shield. I then installed the o2 sensor for the Wideband gauge. I have no codes, so the simulator pretty much takes that sensor out of the loop completely. Just a FYI.....

 

Since the simulator sends the OBD the signal, is it required to fit the 02 sensor back into the exhaust? Why not just plug up the bung, and avoid the hassle of having the sensor in the pipe? Looking at the wiring diagram, it seems to me the simulator is replacing the sensor entirely, so the sensor seems redundant to me.
Hang on, I figured it out now, is it to give any one who might look under your car the impression you have an o2 sensor in place? Like a service technician?

cheers,

 

That would be correct.....

 

the ecu is also checking to make sure the heater part of the o2 sensor is working if you dont do a heater simulator then the o2 sensor still need to be connected but as you know it doenst have to be in a bung or screwed in.. so placing up there where you did will work

 

I was thinking of running 2 sensors: one for regular street, with CAT and standard o2 sensor; and one for track, when running the straight pipe, with o2 simulator and plugged bung.
But, the dealer wants $190 for the o2 sensor! Geez.
Scrap alternate sensor plan...