TeamSwift

I need to know what the wires on a 4 wire O2 sensor do. I want to install one on my 91 vert turbo. I looked but could not find it in search. I know I have read it here but can not find it now . Thanks to anyone that can help.

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Cars and Harleys

Look up a general site that talks about O2 sensors.

Unless you have changed something in particular in your setup that requires a different O2 sensor, I believe it would be a waste of time and money.

GT and GTi use a single wire sensor (narrow band). More recent narrow bands use 3 or 4 wires. The two additional wires are for a heating element circuit designed to get the sensor up to temp sooner to get emissions under control as soon as possible through the O2 sensor in the feedback loop (ie. closed loop control) rather than ECU using pre determined map points only for fueling (open loop). The 4th wire is generally an O2 sensor ground wire rather than using the body of the O2 sensor as a ground

5 wires are true wideband sensors and only usefull if your system has capability to use this.

I put in a three wire into my GTi when I turbo'ed it in an attempt to get that slight improvement to pass emissions testing in Australia. To be honest unless you have a test process that requires a cold start and testing at idle I would just stick with a standard sensor. They are disposable items and would suggest the best value you will get is by putting in a new standard sensor.

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ET 13.138 at 120.2mph

you have 2 heater wires (usualy both white or both black) and from i can remember you have blue and white(or black) from my experiance and one is signal(blue) and other is ground(blk or white whichever is single)
-amer

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93 Swift GT White 3Tech cams, Sandro's chip, Lightned flywheel, Genie exhaust, Cultus header, Intrax springs.
08 Civic Wife's car