Using a wideband for a stock o2 sensor?

[Rennat]

i have a zeitronix kit that im installing right now... and i dont want to just monitor the a/f, i also want to splice the zeitronix into the ecu so it uses the scaling from the zeitronix for the stock o2... but which wire should i cut and connect it to?


its a 90 supra, so the wiring im looking at is for 89-92...

either the VF signal... or the Ox signal..

according to the wiring schematic i want to cut and connect the ox signal from the ecu to the output of the zeitronix... is that right?

 

[GrimJack]

That is correct.

Do you know the cons associated with this?

 

[tbcmorris]

if hes doing it my guess is no

 

[DangoAZ]

I think what these guys are saying is "You don't want to do that... Even if you think you want to do that."

A narrow band "steps" really quickly between 0 and 5 V when you cross the 14.7:1 AFR line. So the ECU is looking for that fluctuation... If you give it the wide band signal, it won't be stepping from 0 to 5, but will be slowly and progressively hovering around in "voltage shades of gray" in the middle. Hence how it can give you AFR over a wide range.

Your ECU WILL NOT be happy.

Even with a MAFT-Pro, my car runs better with a narrow band sensor hooked up than without, because most of the time on the street you are running in closed loop. I would highly recommend using the wide band in addition to - not instead of - the NB. Pay somebody to weld a bung into your exhaust if you have to.

 

[IJ.]

0 and 5V???

are you sure on that?

 

[jetjock]

If he's saying so my guess is no

 

[IJ.]

LOL I'd think "narrow" would be a hint

 

[Rennat]

the zeitronix sends out a 0-1v signal... which is why i was thinking of this...

heres the pdf about the kit... if you scroll down to the section you can see just how this kit works.

http://www.zeitronix.com/installation/ZT2instructions.pdf


and the only reason why i dont just weld in a bung is cause my downpipe is coated, and wrapped... but i would have figured using a wideband as a stock o2 sensor would give you fuel savings because its more accurate which in turn should make your engine run better... but from what your all saying thats wrong?

 

[mkIIIman089]

I have no idea why they're telling you not to. It works brilliantly with the ZT-2.

@ 14.7 switching point, you'll notice absolutely no difference from stock.

 

[Rennat]

I have no idea why they're telling you not to. It works brilliantly with the ZT-2.

@ 14.7 switching point, you'll notice absolutely no difference from stock.

do you own the zt-2 kit?...

 

[jetjock]

The WB's emulated signal is not more accurate. It may be good enough but the NB is specifically designed to work at stoich. The NB is also simpler, cheaper, longer lived, and the signal requires no processing before being sent to the ECU, all of which leave the engine under control of a device less likely to fail. I'm not saying you can't do as you wish because people do it all the time and like Colin have no problems. I'm simply saying it's "better" to leave the NB for those reasons. Just don't expect any driveability/fuel economy gains using the WB.

And regardless of what you do don't power the WB's electronics off a crucial circuit that'll shut the EFI system down if something happens. Yeah, I know it's probably fused, but it's still bad practice...

 

[Rennat]

And since i know your a electronics guru... could i just tap the wire into the stock ox signal and not have to cut it? and just unplug the stock o2 sensor?

 

[mkIIIman089]

I should mention, if I were simply going to run at 14.7 switching point I would not be using the ZT-2 as the ECU feedback sensor for the reasons jj outlined above.

 

[jetjock]

^ Wtf does that mean? Are you callin' me out?

Rennat: yes..

 

[GrimJack]

And since i know your a electronics guru... could i just tap the wire into the stock ox signal and not have to cut it? and just unplug the stock o2 sensor?

Yes.

However, you will also need to put a resistor in place for the heater circuit on the stock O2 sensor wiring, or you'll get an evil code all the time.

 

[isnms]

Weld a bung on a test pipe or better get the exhaust depot high flow cat with a bung already welded on. Keep both sensors. That's what I did and yes I have the ZT-2.

 

[DangoAZ]

^ I think that's good advice.

Sorry about the 0 - 5 V in my previous thread. My mind was already spinning down Vf paths when I wrote that. I'm an idiot. :slap:

Smart Guys: Thanks for calling the bogus info out... My bad. Glad there are so many people on here to keep the story straight!

Rennat: Hope you found a solution that works for you. Please keep us posted. I'm interested to hear what you learn.

 

[mkIIIman089]

Gary: oh jeez.... here we go...

Just saying if the only reason for doing it is because he's too scared to get a bung welded on... he's better off leaving the stocker for ECU feedback.

Rennat - yes, and I've been running it for 3ish years as the ECU's sensor - not because I don't have a separate wideband bung...

 

[Rennat]

I could easily drop my cat and weld a bung in a matter of minutes... i made my own catback... so the welding isnt an issue, and i can get the bung for like $3 at the local exhaust shop...

i think i'll try it out, and if i do notice issues i'll switch back.

mkiiiman089 - so why do you use it as a main sensor? piggyback ecu or something?

 

[mkIIIman089]

No, tuning. Someone else can probably elaborate, I'm bored of explaining my setup - it just takes too much effort to get people to understand.