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Oxygen sensor needs air from outside!

W

wim hoppenbrouwers

NAXJA Forum User
Location
Netherlands europe
Hallo Jeepers. I renewed my oxygen sensor.
I bought an original , because the strange sensor didn't have the right connectors. I do understand now, why they selling the sensor complete with the wires and the connector. The wires are special. They are hollow, also the pins in the connector. So don't solder the wires or put dielectric grease on the connector. Keep the original wires and connector.
The sensor is comparing the inside of the exhaust with the outside atmosphere.
It is doiing that through the connector and his wires.
The difference in oxygen levels between the exhaust and outside air in the sensor causes voltagevariation.
Grease or underbodycoat will block the airflow.
Heynes never tell us such important info.:laugh2:
 
wim hoppenbrouwers said:
Heynes never tell us such important info.:laugh2:
Click to expand...

That's why you take the time to read the inserts in the parts packages.

Even the FSM soes not contain all the inforation you will need as a beginner. Each book assumes a level of competence by the reader.

The only book I have ever seen that takes the layman completely though the complete process was "How to keep your VW alive for the complete idiot" Mr. Muir even told you where to find the bolts, why you were doing things, and the basics of how it worked.
 
This is the first time I have ever heard that.
 
Me too. I read it in a technical magazine. So I thought that 's important info to share with the other guys from :NAXJA:
Older style oxygen sensors had a tiny hole in the body so air could enter the sensor. But mud and water can block the airflow.
You can't believe it ,that the sensor breathe through the wires and connector.
I did a test with a piece of the wire of the sensor. You can blow through it.
The wires are stiffer then normal electric wires.:wave1:
 
Last edited:
goodburbon said:
Doesn't sound right to me.
Click to expand...

The oxygen sensor works like a generator and when hot it produces voltage.
Inside the ventilated cover (in the exhaust) is a zirconium body.
The body is coated on the outside with platinum.
The difference in O2 levels between the exhaust and outside air causes voltage. So how is it getting air from the outside?
The higher the diff.,the higher the voltage.:wow:
 
Last edited:
goodburbon said:
Doesn't sound right to me.
Click to expand...
I was trying to be a bit more politic till we get some other input, I've not really dealt with O2 sensors so know enough about how they actually operate, only how they are supposed to work. It does sound plausible and for all I know Europe had a different setup than the US. I'm going to ask around at the shops I take care of and see if this is possible.
 
I didn't realize this wasn't as common knowledge as I thought... I guess the study in boilers and boiler controls paid off a lil. ;)

o2const.jpg
 
Also on all of the sensors that we use here the reference air sample is not vented, but sealed. Granted, this is not for Oxygen, but the sensors operate on the same principles.
 
So what I'm confused about is what year/model xj's had o2 sensors with an air tube. I've heard of them but never actually known a specific vehicle to use them, much less an xj. None of your basic four wire sensors have an air tube. Maybe it's a European thing... :dunno:
 
wim hoppenbrouwers said:
There is a story about the ventilation in the FSM of the cherokee 2000
page 858 out of 1528. I coudn't find it, but mayby you guys.:laugh3:
Click to expand...

"An O2 sensor is a galvanic battery that provides
the PCM with a voltage signal (0-1 volt) inversely
proportional to the amount of oxygen in the exhaust.
In other words,if the oxygen content is low, the voltage output is high;
if the ogygen content is high the output voltage is low. The PCM
uses this onfo to adjust injector pulse-width to achieve the 14.7-to-1 air/fuel
ratio necessary for proper engine operation and control emissions.

so far it is known.but;:yelclap:

An o2 sensor must have a source of oxygen from outside of the exhaust stream for comparison.
Current o2 sensors receive their fresh oxygen (outside air) supply through the wire harness. This is why it is important to never solder an o2 sensor connector, or pack the connector with grease." :shhh:

from Cherokee 2000.

p.S. Also interesting: 4x4Wire-Tech: Time to Replace the O2 Sensor on your 3rd Gen To... LOL They mean on your Jeep.
 
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I know that my Bosch "wide-band" sensor has no "outside" air source.It has to be calibrated at "ambeint" temp in free air.
 
mjma said:
could explain why a new "universal" O2 sensor didn't fix my O2 code...
Click to expand...

Hallo. I think that the universal sensor is mayby a zirconia type.
I find out that Nissan,Jeep and Subaru use a lower output (0-1 Volt) Titania sensor. Bosch don't make them.
Titania style sensors do not depend upon outside air for reference when doing its job.
Therefore,in trucks that are used in off-road. the reliability factor is more important than high tech.
Zirconia sensors will not perform if they are covered with mud or grease blocking the ability of the sensor to compare outside air with the exhaust gases.

thanks NGK and patience :NAXJA: to read my posts:shhh:
 
goodburbon said:
Not noticable in this diagram

http://www.boschautoparts.com/NR/rdonlyres/A4F80870-678D-4115-9A3A-1A86CBC439D7/0/PlanarSensor.pdf
Click to expand...

Hallo Goodburbon. I received a memo from the tech.dept of Bosch.
They told me that all Bosch Oxygensensors are Zirkoniumtypes.
They are active ones and so they generate their own voltage.
They need a microscopic flow of oxygenions. The Zirkonium is becoming airopen from 350 C. The tiny hole in the sensorbody is over already for 30 years.
Now the ambient air is going into the sensor by all the types through the black wire. Black is the signalwire. Therefore it is important to keep them clean in the connectors. Solder wil block the airflow. Spraying connectors will kill it.
There is no difference between the original and the universal ones.
The connectors are also special.
I have spoken with a lot of techical people and visit the last 3 weeks many sites about the Lambda or o2 sensors. The last memo from Bosch was the one with the most info.:compwork:

I think that I am a oxygen addict.
 
Last edited:
wim hoppenbrouwers said:
Hallo. I think that the universal sensor is mayby a zirconia type.
I find out that Nissan,Jeep and Subaru use a lower output (0-1 Volt) Titania sensor. Bosch don't make them.
Titania style sensors do not depend upon outside air for reference when doing its job.
Therefore,in trucks that are used in off-road. the reliability factor is more important than high tech.
Zirconia sensors will not perform if they are covered with mud or grease blocking the ability of the sensor to compare outside air with the exhaust gases.

thanks NGK and patience :NAXJA: to read my posts:shhh:
Click to expand...

this is quite right, but on the fact that Bosch does not make Titania sensors, they do. i have one on my 86 Nissan 300zx. they are used on there turbo based models. also the Titania is not voltage generating as the zirconia it generates logic high or low (1 - 0) depending on the ratio of fuel to air. so it is constantly swinging from rich to lean. i am also going to add there much more expensive.
 
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