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Wide band O2 Sensor

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I just purchased a wide band O2 senor and Gague from iWire.

I am also upgrading my turbo, uppipe, downpipe, and catback exhaust.

My question is:

What do I do with the TWO original OEM O2 sensors that I took off the exhaust manifold and rear exhaust cat?

Attached Files

Is the factory ECU still controlling the engine? If no, simply unplug the NB sensors and set the WB sensors in the standalone ECU accordingly, assuming the WB signal first goes into it, then being sent out to the gauge.

If the stock ECU is still in place and you do want it to perform in, sort of, open loop, fitting a resistor ( I do not recall how many Ohm) instead of the NB sensor downstream will likely keep the MIL light off.

It is advisable to have control over the mixture, I guess you have that covered.

Afterall, this is not a proper way of EFI "tuning" in my opinion, rather a cumbersome workaround.

Hey Dom,

Yes, the factory OEM ECU is still controlling the engine. I'm using ECU Flash/ECU Edit and ROM raider to tune.

What made me ask my question was that on iWire's site they have an install of a wide band O2 sensor proximal to the turbo (at the head of the down pipe) but then they go on to say to plug the rear O2 sensor as its not need anymore.

I wasn't sure, but I'm thinking I can use the wide band up front and get a new narrow band in the rear? Thoughts?

It looks like you have a Subaru with an EJ turbo engine. The front o2 sensor must remain in use, reinstall in the exhaust manifold and hook it back up. What you got from iwire is for the rear o2 circuit.

Oh good point!! I didn't catch that.

Now will this set up (wideband sensor on rear O2) decrease the sensitivity of reading the wide band?

Can I purchase a wideband for the front O2 sensor and have wide bands on both? One connected to the ECU and the other connected to the Gauge?

The stock ECU is only designed to work with the stock OEM front o2 sensor, and due to placement pre turbo, it's not suitable for accurate readings in boost anyway, so the stock sensor does a great job and putting an aftermarket wideband there is not advised.

To tune moderate to high load conditions, using a wideband sensor post turbo is typical. Yes you can install a wideband post turbo, in addition to the stock rear o2 sensor being post turbo.

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