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Alfa Romeo 2.0 turbo O2 sensor in charge pipe

Understanding AFR

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I bought a new to me Alfa Romeo giulia 2.0 turbo it has a weird O2 sensor in the charge pipe coming from the turbo to the intake and I can't figure out why it's there

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While the picture came through a bit blurry, it sure looks like what you described! I've not seen this before and curious to hear more if anyone on the forum has experience with that vehicle.

Are there any part numbers on the sensor in question?

No part numbers but here's a better pic

Attached Files

There's a bit of a number in that picture, but not enough of it is visible to reverse out.

It definitely looks like a Lambda sensor, other than a black sheath, it looks to be identical to the lambda sensor in the down pipe. I have no idea why it would be there though, or what it is used for.

Weird, initially wondered if it might be a pre-heater for cold weather, like on a diesel, for better fuel atomisation and lower emissions and, maybe engine performance - but that's unlikely.

Second was it's to monitor the oxygen content in the intake charge in highly polluted citiues where the oxygen percentage might be lower, or maybe it's measuring the EGR/oxygen ratios - so it's not only measuring mass but quality, too. But that also seems very unlikely!

No doubt be a WTF moment when you do find out - good luck with that!

Reading this forum, it looks like there is confirmation from the workshop manual that it is indeed a Lambda sensor. Why is another question entirely. Knowing how a Lambda sensor works, with it requiring the EGT to maintain it's operation, sounds like the heater would be constantly running to maintain the temperature that the Nearst cell requires for operation.

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