Is the O2 sensor a necessity?

[c-rad]

In the FSM, it says that only the models with catalytic converters came with O2 sensors. My friend here said that when he lived in Japan, him and his friends just drove without them. Is this possible? Also, if you were to run a .bin file from a non-catalytic car, would that eliminate the need for one as well? I'm just trying to simplify everything as much as possible.

[float_6969]

I suppose you could, but you'd want to retune the ECU to deal with it. You're gonna get crappy gas mileage though.

[c-rad]

Well, that's why I am wondering if a .bin ECU file from a non-o2 equipped car would negate the need for one.

[themadscientist]

It would just run off the maps with no real-time correction as I understand it.

[float_6969]

You could try it I suppose. It couldn't hurt.

[mikesim]

i bought a downpipe with decat, but i was worried that if there were a sensor in the stock cat, it would cause problems not hooking it back up. i'm still going to run the sensor in the up-pipe.

[slownslurious]

man I know its not a ca, but my friend's evo has an 02 after the cat and we unplugged it when we bolted on his 3" turbo back (it didn't have a bung for it) and before we took it in to have a bung welded on it, that thing ran rich as ****... back firing on every shift, bogging off idle, etc...welding an 02 bung in is pretty easy and the sensors aren't too expensive, I think it would be easier to add an o2 than to reflash the ecu to run with out, unless you have some inborn hateness for 02 sensors.

[c-rad]

You guys are talking about something totally different. You are talking about the O2 after the cat which is an OBDII thing for making sure the cat is working. The front O2 is usually there to keep the A/F in check so the cat isn't burnt up.

[float_6969]

OBDII is WWAAAAYYY more dependant on O2 sensor's than Nissan's OBD I/ECCS system, although it's still pretty reliant upon it and the ECU will default to a rich setting and your mileage will plumet, not to mention carbon buildup and plug fouling. It's that that big of a deal to have an O2 sensor hooked up.

[Coldspawn]

Is this possible?

Yes, it will run on open loop. Meaning it will run on the base maps without the correction of the 02 sensor. Your car runs on open loop for the first few seconds or minutes (depending if the 02 sensor is heated or not).

If you disconnect it with a ECU that requires a 02 input, it will throw a code.

Also, if you were to run a .bin file from a non-catalytic car, would that eliminate the need for one as well?

Well, that is a bit of a trick question. If the bin file can disable the need for 02 input, you will run on open loop and not have code. Just because it does not have a catalytic convertor, does not mean it does not have a 02 input.

[NeedCAforS13]

my car ran different as night and day when I put a new o2 sensor on it.... went from smoking like crazy and running rich, to idling perfect and running great. Why don't you want to run an o2 sensor chris?

Sean

[F3600]

without a o2 sensor my car was running the same. I didnt see a change in mileage and smoke or anything.

yI was running on a pre-cat Ecu too. If you have the .bin just try it

[c-rad]

without a o2 sensor my car was running the same. I didnt see a change in mileage and smoke or anything.

yI was running on a pre-cat Ecu too. If you have the .bin just try it

Yeah, I am going to just burn two eproms... one from a non-cat car and one with a cat. I'll try em both and see what happens.

Sean, it's not that I don't want to run an O2 sensor, I am just wondering if it's necessary. I plan on running a PLX wideband anyway and it has the narrowband output, so I will be okay either way.