02 Wideband and stock 02 question.

[Thrush]

I am trying to get info about Stock and Wideband O2 sensors.

What is the difference between the two (wideband vs. stock)? I am assuming that the wideband has a greater range of being able to tell what the A/F ratio is. This seems to be obvious. I just can't seem to find what is the range of the stock compared to the wideband (assuming all widebands are similar or the same)? 9-20?

Also how do the stock O2 sensors work with the computer? I believe that I read that the computer alternates between the two sensors and takes an average between the two then gets the A/F ratio from there. Please correct me if I am wrong.

 

[jrichker]

Wide band O2 sensors will not work with your computer. The computer's firmware program is not designed to be compatible with wide band sensors. Wide band sensors have a more linear output that looks like a slope then plotted on a graph.

The stock O2 sensors "switch" between .2 volt lean and .6 volt rich with a curve that looks like the drop off a high cliff. The curve is almost straight up and down, so the voltage shoots up from .2 to .6 and back down again 2 or more times a second at cruse.

Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. The computer pins are 29 (LH O2 with a dark green/pink wire) and 43 (RH O2 with a dark blue/pink wire). Use the ground next to the computer to ground the voltmeter.
The O2 sensor ground is in the wiring harness for the fuel injection wiring. I grounded mine to one of the intake manifold bolts

"When the mixture is lean, the exhaust gas has oxygen, about the same amount as the ambient air. So the sensor will generate less than .4 volt. Remember lean = less voltage.

" When the mixture is rich, there's less oxygen in the exhaust than in the ambient air , so voltage is generated between the two sides of the tip. The voltage is greater than .6 volt. Remember rich = more voltage.

Here's a tip: the newer the sensor, the more the voltage changes, swinging from as low as 0.1 volt to as much as 0.9 volt. As an oxygen sensor ages, the voltage changes get smaller and slower - the voltage change lags behind the change in exhaust gas oxygen.

Because the oxygen sensor generates its own voltage, never apply voltage and never measure resistance of the sensor circuit. To measure voltage signals, use an analog voltmeter with a high input impedance, at least 10 megohms. Remember, a digital voltmeter will average a changing voltage."
Charles O. Probst, Ford fuel Injection & Electronic Engine control

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst :ISBN 0-8376-0301-3.

It's about $20 from Borders.com see http://www.amazon.com/ . Select boo...very good, and I found it to be very helpful.

 

[Lxpony]

a WB o2 has a much broader voltage spectrum thus more accurate...

 

[Thrush]

So the Stock O2 sensors only produce a .2 or .6 outage and the in between is not detectable because of the sensors inability (feature) to output a voltage in the middle range? Do you know what the curve is or what the Hi/Low is? .2=11 .6=17?

One of the reasons why I am asking is that I am getting a Tweecer and was going to be viewing the volts at the same time the EEC is. So I will be checking them to see how good they are as well as some other stuff.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst :ISBN 0-8376-0301-3. Thanks. I will defiantly be checking this book out. I already had it on my list of things to do.

 

[Lxpony]

correct- WB use a much broader voltage range which is much more accurate-

I use a AEM wide band but got it for almost 450.00! this site here it is much cheaper-$ 350.00 is a great price-

http://store.yahoo.com/sgpracing-store/aemuewiafmo.html

 

[Thrush]

One of the things I was looking for was the graph that I hopfully attached correctly. I also found out that there are WideBand O2 sensors that will work with the EEC outputing analog narrowband. There are also others out there that do datalogging as well narrowband.

Does anyone know how the EEC functions with the two O2 sensors?