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HI
Is it possible to replace old stock single wire O2 sensor with 3 or 4 wire O2 Sensor. Car is Suzuki Cultus (G10B engine).
 

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Phil - what would would happen if he installed a 3 wire sensor, connected the signal wire, and left the heater wires loose?
 

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would it give the same output signal range tho?
I thought the idea of the heater was to give the sensor a stabilised temperature reference for the sense element. I've never tried it or looked at the outputs.
Theoretically it should work as the manifold is obviously getting hot enough for a "1 wire" to work, so it should allow a 3 or 4 wire to function sans heater. If it doesn't, then mix will be affected.
I have replaced 1 wires with 3 wires on cars with after market headers where they didn't get hot enough for the 1 wire to correctly track the mixture and that certainly worked.

Interesting thought, wonder if it will work.
 

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would it give the same output signal range tho?

Interesting thought, wonder if it will work.
The OBDii range is .01 - .99 so the only issue would be the heater, provided the sensor is not too far down the pipe it should heat up maybe just a bit slower...
 

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The OBDii range is .01 - .99 so the only issue would be the heater, provided the sensor is not too far down the pipe it should heat up maybe just a bit slower...
yeah I agree totally, my only concern is the reaction time, but if the 1 wire is getting hot enough, then a 3 wire should work with the heater disconnected.
 

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The purpose of the heater is to get the engine into closed loop mode sooner, and thereby reduce emissions.
 

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The purpose of the heater is to get the engine into closed loop mode sooner, and thereby reduce emissions.
I disagree with your statement partially.
While it does get it to operating temp quicker, the type of cell plays a big part. I can also now confirm you can't just replace a 1 wire with a 3 or 4 wire as they are constructed differently. I have found the following which helps explain the difference.

The AFR sensor generally is a very sophisticated measuring device that must be kept at a constant temperature to measure accurately, so the heater is critical to its operation. This also depends on whether its a zirconia or titania based sensor. They behave totally differently, the zirconia create a voltage while the titania changes in resistance.

In a standard O2 sensor, the cell wall is a thin wafer of zirconia that reacts to different concentrations of oxygen in an engine’s hot exhaust stream (660 degrees Fahrenheit or 350 degrees Celsius). When there is a high concentration of oxygen on one side of the wafer and a low concentration on the other, the oxygen on the “high” side will cause ions to flow through the wafer to the “low-oxygen” side. The flow of ions creates a voltage that’s picked up by the electrodes attached to each side of the wafer. This type of sensor can generate about 1 volt, and it’s completely passive.
The sensor’s zirconia wafer is shaped like a thimble, and the outside wall is exposed to exhaust gas while the inside wall is exposed to ambient air. One electrode is attached to the sensor body so it’s grounded at the exhaust pipe. That means that only one wire is needed to send the voltage signal to the PCM. A hollow sheath around that wire provides outside reference air to the inside of the thimble.

A titania sensor is very different. When heated, the electrical resistance of titania changes as the concentration of oxygen surrounding it changes. A titania sensor does not generate voltage... it changes the output voltage of the current flowing through it.
The sensor element is a flat wafer with electrodes on either side, so it’s sometimes called a “planar” sensor. The PCM supplies a constant reference voltage to one electrode and measures the voltage drop through the element at the other electrode. Since the reference voltage is typically 5 volts or higher, this sensor produces a nice fat signal that reacts much faster than a Nernst cell, and it doesn’t need reference air either, so it’s smaller and less vulnerable to contamination. But like the zirconia sensor, the output signal is not linear; it rises or falls sharply on either side of stoichiometry, so it’s still only capable of indicating a rich or lean air/fuel ratio.
 

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What I will tell you is that I have taken a 4 wire sensor off of one of my vehicles, connected a voltmeter between the signal & ground wires and then heated it with a butane torch and watched it generate that 1 volt signal, confirming that it does produce that voltage "passively" - this would suggest that there MAY be some 4 wire sensors that can be used in place of a 1 wire sensor, if the ground lead is connected to the exhaust pipe - I'm out of country at present, but once I get back I can take a photograph of the 4 wire sensor and you'll see it has the thimble shape described - I can also verify at that time whether or not the heater circuit gets powered off as I believe it does.

I've never heard of these titania sensors, but, it would seem to me that they would need to be a 5 wire sensor since they need a 5v reference from the ECU, along with the signal, ground & heater connections..

The reason why I phrased my earlier reply as a question is I've never tried it and don't know for a fact that it can be done - I've never actually seen a 1 wire sensor - I can remember being curious about it some years back and asking our "resident ECU guru" at the time (Rhinoman), and I believe his answer was similar to the one I gave earlier, in theory, it can be done.
 

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I am also curious, single wire sensors have been around for years, and only on the "upstream" sides of cats, or very close to the manifold if no cat is fitted.
I will be interested in what you find.
 
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