Bank 1 Sensor 2 (right or left?)

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mwise101
Posts: 1
Joined: Wed Nov 16, 2011 1:32 pm
Car: Infinity I30

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Can someone help me in locating this oxygen sensor? It seems it's a post cat sensor, but according to rockauto there are 2 sensors after the cat. This is for a 2000 I30. This is for my brother's car so I don't have it here to look at. He's an hour and a half away.


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loystock
Moderator
Posts: 2144
Joined: Sun Sep 21, 2003 9:12 pm
Car: 10 Pilot, 97&03 Q45s, 97 I30 and 06 M35 Sports (04 G35 & 99 I30-RIP)
Location: San Jose, CA

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First, the transverse mounting of the VQ engine places Bank 1 (cylinders 1-3-5) close to the firewall while Bank 2 (cylinders 2-4-6) is close to the radiator. So if you are under the car, the front exhaust pipe is for Bank 2 and merges with Bank 1 exhaust pipe downstream of Bank-1 Pre-Cat (This is where some mechanics may get confused).

Front O2 sensor in general is mounted before (upstream) the Pre-Cat while the Rear O2 sensor is mounted after (downstream) of the Pre-Cat. As applied to VQ engine, FRONT O2 sensor has 3-wire (power, signal and ground) while REAR O2 sensor had 4-wire (power, signal, ground + dedicated signal ground).

On this particular generation of cars, there are 3 catalytic converters - Bank 2 Pre-Cat (in front of engine) mounted vertically, Bank 1 Pre-Cat (below the engine) mounted horizontally and then the main/rear catalytic converter.

The HO2S2-B1 (Heated Oxygen Sensor, Sensor 2 - Bank 1) is mounted in front of the Bank 1 (as described above) with a WHITE harness and connector on the radiator side. This is a lot easier to replace. The OEM Bosch sensor is13374 @ $120 while an OEM-compatible NGK/NTK is 24574 @ $95. And you're in luck...it's on sale right now at Amazon for @ $66.


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