Ok this is a very n00b question and I do apologize in advanced, but if I turn o2 feedback off, am I reading it right when it turns off the closed loop feature of the o2 sensor?

If so, is the o2 sensor even required at this point if I have a wideband sensor to tune with?

 

OH i have searched all over on the o2 feedback function on here and found several useful threads, my main question is the retarded second half (do i need the narrowband hooked up while using the wideband if the o/2 feedback is off)

 

No.

 

With the O2 FB turned off, you now can recalc the whole now, and you can tune idle and cruise leaner than Mazda had it.

Be sure to disconnect the air pump while AFR tuning otherwise the AFRs will show leaner.

 

Thats what I figured. My plan was to unplug the airpump for right now until I can get a pulley bracket to remove it, turn O2 feedback off, install the Wideband into that same bung (its about 1.5ft down the downpipe) and retune the idle and cruise tables

Thanks arghx and chuck!

 

Do you mean to unhook the air pump while tunimg idle and cruise or when tuning the whole range including WOT? I would assume it could damage the cat if the air pump was disconnected too long.

 

It depends on turbo configuration and O2 WB placement.

The stock systyem pumps air into the exhaust manifold and cat.
If the WB is in the DP or tail pipe , it would get air and lean out up to about 3000rpm. In the tailpipe past 3000 rpm the cat affects AFRs also.

I run a single turbo with the air pump and no cat except for E testing.
My air pump pumps to the MP, so the DP is always good for AFR testing, and tail pipe only after 3000 rpms. I always disconnect the AP for any testing to be sure.

 

Forgive the ignorance, but to be clear:
- stock, the AP pumps air not only in the cat but to the exhaust manifold so as long as the AP is running (below ~3000rpm) any O2 sensor is going to read a-rtificially lean, bot in the dp and in the tailpipe.

- with your single setup, the AP doesn't direct air into the exhaust manifold, only into the MP/cat so in your case an O2 sensor on the dp will read correctly at any rpm (whether the AP is running or not) but a sensor in the tailpipe would read lean even with the cat out because the of the AP.

Take home message: Unplug AP when tuning A/F if you have a stock setup.

Am I right?

 

^^^bump this last question please.

 

So i have a question to. I didnt want to start a new thread as its pretty on topic for this one. I just got a new downpipe and it only has one o2 bung. Can i just turn my o2 feedback off and not have a check engine light? I have a wideband and was running both in the old downpipe but i am taking it to get ceramic coated tomorrow and dont really have time to have one put in. I would just run my wideband then. Thanks

 

you can run just the wideband, with no CEL. You would want to turn o2 feedback off. although most widband sensors also have a channel for narrow band as well. It's still best to tune with o2 feedback off you can get better mileage this way also by tuning cruise maps leaner.

If the bung is too close to the manifold outlet you can burn up sensors quicker. heated wideband o2 sensors are best put in the end of the downpipe just before the cat. So you might consider this depending on where your 1 bung is welded.

 

The PFC does not use the CEL for any warnings/errors. It does not even blink like the stock ecu does when the key is first turned on.

In fact: we have to do a wiring mod to get the CEL to work with the injector duty cycle and knock warnings. With this mod the CEL will blink when first turned on.

 

^Thanks guys thats what i wanted to know.