I need some information about oxygen sensors. The sensor on my '87 Ranger is bad. It has a heated sensor with three wires. Now for my question. I have been given a sensor off a newer Ranger that is practically new. The only difference is that this sensor (it's a Ford badged sensor made in Japan) has four wires, two of which are white. The sensor on my truck only has three. The connectors are the same, except for the extra prong on the four wire one and the sensors are pretty much the same apperance wise.

Can I use this four wire sensor to replace the one on my truck that has only three? The connectors and sensors seem to be the same except for that one extra white wire.

 

I've been looking online and reading all kinds of stuff but haven't found an answer to this question. Anyone know?

 

I remember reading about this over at TRS. Is the extra prong in the connector coming from one of the white wires?

If so I believe that is the oxygen sensor you're supposed to use now, which is why two wires are white.



Allen

 

Might be they updated it to keep with emissions and all that crap.

 

I remember they were saying it allowed the manufacturer to make only one instead of two different kinds.

So basically it means that one will also work on my 95 Ranger.



Allen

 

Yeah the extra prong in the connector is from the extra white wire. I can't find an updated Motorcraft O2 sensor for my truck to look at, but the replacement Bosch sensor only has three wires. Of course the Bosch sensors seem to be a different design than the others.

I'd think that the sensor would work ok, I was just looking for confirmation.

 

Here's what I found on the BOSCH website

<table bgcolor="#ffffff" border="0" cellpadding="0" cellspacing="0" width="433"> <tbody><tr><td colspan="2"></td></tr><tr><td></td> <td width="433">Q. I have a Bosch original equipment 4-wire sensor. What do the wire colors mean?</td> </tr> <tr><td colspan="2"></td></tr> <tr><td></td> <td>A. All Bosch 4-wire sensors have a black wire for the signal, a gray wire for ground and 2 white wires for the heater. Note: the wire colors and functions on non-Bosch sensors are not necessarily the same as on Bosch sensors.</td> </tr> <tr><td colspan="2"></td></tr></tbody> </table>

http://www.boschusa.com/AutoParts/FAQs/OxygenSensors/


Maybe your 3 wire has the ground wire common to both the sensor and the heater?

 

So it's just an extra heater wire. Thanks for that info.

 

I would go ahead and say use only Motorcraft parts, but it's obviously a little late.
Give it a shot and tell us how it turns out.

 

It may not be an extra wire, but both ends of the heater itself. (just a guess). Don't know what the current requirements are - might be high enough to warrant running 2 leads out from one end of the heater.

Wish I could find my service manual CD on my 93 Ranger so I can lookup the wiring of my 4-wire O2 sensor. That'd tell me if both white wires are the same/redundant.

I found this for the pinout of a 3-wire O2 sensor.

http://www.theguestroom.net/manuals/...%20Sensors.htm

 

I just changed out the stock OEM O2 sensors from my 93 Ranger. (156K miles - I think they needed to be changed :-) )

They were BOSCH with the bosch logo and a ford pn on them.

Bosch is OEM for a lot of mfgrs.

 

I think NGK makes 02 sensors for Ford, too. Depends on the application.

 

The sensor I have (the 'new' one) is made by NGK. So is the consensus that it should work ok? It is off a Ranger, just a much newer one than mine. And it has an extra white wire.

 

The extra wire is sensor ground. The older models have the ground through the engine block, looking at my Haynes manual. Newer models, for emissions accuracy, have the ground separate. Your new sensor should work fine; just ground the extra wire.

Everybody makes sensors. The OEM sensor on my F150 was NGK. I replaced it with Bosch for $40.

 

With a 4 wire sensor, the 2nd white wire is where you ground the heater. It is otherwise identical to a 3 wire sensor. A 3 wire O2 sensor has a signal (purple or green in the case of most Fords), signal ground (typically black) and heater wire (white); the heater is grounded to the case. I suspect the 2nd heater wire was added to ensure that the heater always had a good ground.

1 wire sensors are unheated and ground the signal through the body of the O2 sensor, but there is typically a ground wire attached somewhere on the exhaust nearby. They can be "upgraded" to 3 wire sensors by adding a switched 12v power source to the heater wire and attaching the aforementioned ground wire to the O2 sensor ground. This *may* give you a little extra fuel economy since one of the inputs for closed loop operation is when the O2 sensor starts switching above a certain voltage that is only attained when the sensor is warmed up.