I see, what looks like, most like the AEM 30-4110 wideband o2 sensor. Has anyone used it to calibrate the AFM on an injected L28? I'm sure its great for the carb's but how about FI. I was thinking of having the bung installed on my exhaust and just leaving the o2 sensor there and when I need to make adjustments to the FI for emissions testings I would hook up the gauge where I can see it while making my adjustments. Or maybe not mess with installing a bung and just sticking the o2 sensor in the end of the exhaust? Need a little advise on this one guys.

If your not planning on running a guage and monitoring full time is suggest putting a plug in the bung. They are known to foul fairly easily and aren't that cheap to replace. I don't see why sticking it in the back of the exhuast would be an issue.

I think the sniffer in the pipe is the most flexible. As well it is where emissions tests are done.

The tail pipe a/f follows the same values at the header in time. The only difference is that some dilution occurs and transients are smoothed out.

Thanks guys, thats what I wanted to hear.

This will make you happy:

http://www.classiczcars.com/topic/47234-af-monitoring-points-info/

Perfect. Just what I needed. 

I'm going to make an air-fuel ratio meter finally.  I finally have reviewed all the relevant information, like narrow- or wide-band sensors, or how many wires on the sensor.   I found a schematic and developed a PC board, and ordered the parts.  I still need to get the sensor (a wide-band sensor) which I could get from the JY still this year, weather permitting.  I'd like some advise as to which types or models of vehicles would have a  wide-band sensor.  I suppose I would just take some vice grips and climb underneath to unscrew the thing,.

They are about $10

By-the-way:  just inserting an oxygen sensor into a tailpipe is  not going to be enough.  You need to push it as far as possible so you will get an honest reading.   I've read some DIY discussions on this subject where the builder chose  a length of small-diameter copper pipe, or a long welding rod, etc.

Good luck with vise grips. Oxygen sensors can become very stubborn from heat and sometimes rust. They make special wrenches for them but you can probably come up with something better. I would try open/ boxed end wrenches or even a large adjustable wrench. Then would go to channel locks before I went to vise grips, leverage is your friend...

I'm going to follow this thread Tom. I never got around to doing anything and then just forgot about it. But, am curious what you come up with.  

After all the work to design a PCB and collect the parts, I found a kit ay jaycar in Aus.  https://www.jaycar.us/display-fuel-mixture-module-ego-10led/p/AA0374

Right now, I just want to get 'a' sensor so I can play around with the thing,  Sometime after Christmas, I will look into ordering a new sensor.

BTW  I figure you can get a sensor from any 4 cylinder car? just look aft of the catalytic converter?  Maybe there's one even before it.

I'll let you know if there's any progress, but the thing really isn't of much use unless you thread it into the header pipe...

The reason this sensor interests me is that I'd like to figure out what I can do to fix the lean condition you get when you stomp on the throttle pedal.

Edited December 3, 20168 yr by TomoHawk

Many new cars have them in the down pipes before the cats. Some vehicles have three. One on each bank and one behind the cats. It shouldn't matter on the cylinder count. The sensor doesn't know the difference. If you can find one in the down pipes you may be able to remove it from under the hood instead of trying to get under the car in the JY