Interesting project, Air/Fuel gauge
 

http://www.scirocco.org/tech/misc/afgauge/af.html

Can't see why it wouldn't work. If I get the time tomorrow, I will head down to the electronics store near me, and build one. But, I won't have the time to drill and weld in a bung for the oxygen sensor. I'll see if I can test it on my buddies room mates car. Build two perhaps, so he will let me mess with his car, keep one as a gift... haha

I'll let you guys know how it goes.

Unless you beat me to it.

you can use an exisitng O2 and piggy back off the signal?

Well.. It's an actual voltage out between .2v-.7v. 0-1v total range. You should be able to do that, but depending on the demands and system type, I would not say yes 100%. Off the top of my head, I can't see why not for any of our systems.

so this is just a verification of what your stock O2 sensor reads? it shows air to gas in the exhaust?

That's all an O2 snesor does. It determines the amount of oxygen left in the exhaust. By doing that, it can tell what the fuel to air ratio is.

If you have a good multimeter you could actually use it to read. This is just a way to build a display to show what an o2 sensor is reading.

Why do companies charge so much for an air/fuel meter? Because people are sheep.

I use an autometer A/F gauge I got from ebay for not even $30 brand new. I think it's a procomp, I forget exactly I got whatever matched my Boost/Vac gauge.

i always assumed (without really thinking about how too much) that a ratio gauge would show intake mixture. i don't really see how it does you any good to look at the exhaust mixture. the sensor is already compensating to make it the right mixture

If your car can compensate than coolio.

Mine has three carburetors that have to work right with each other, and the engines requirements. I could really use one.

And what makes you so sure that your engine is running at a good ratio at all times of load? What if you are losing power you don't know about because the system is not working correctly and you don't know it. Like one injector that had a bad spray, or is clogged a little?

They come in handy.

I wish I had active exhaust temps from each cylinder. But, this is not like the engines I work on at work. haha

So, balanced carbs, and an air fuel meter will help me tune my car without hours of plug pulling, and driving.

that is true. it helps a lot to get your carbs tuned. i know a few people that use them just for that. i guess i was just hoping to look at what mixure was started with and compare it to the mixture at the back

That would be cool. But, to see the actual mixture in the mix before it sparks would require some sort of sensor in the actual cylinder itself. Because, only after it pulls all the air in, and fuel, or injects the fuel. Do you actually know the actual mix before it sparks.
Intake would not be the place to test.
So the only logical place to test, is after it burnt.