Using volt meter as A/F meter

carl

carl

True Classic
I have two charts to use in reading voltage off a volt meter as an air/fuel meter (when wired to an 02 sensor). I'm hopeless at doing attachments here but can email them to anyone who wants them (then you can post them here!).

Email me at carl.friedman*uspto.gov if you want them.

carl
 
Wide- and Narrow-band

Hi Carl,

I used to have a narrow band A/F gauge in my X.
From my experience, since it only shows whether you are on the rich or the lean side of stoic, its use is very very limited.

Since the advent of the wide-band meter, the narrow-band stuff is very obsolete IMHO. I used a friend's Zeitronix setup to tune the dual DCNF on my X - simply awesome! There is no alternative, maybe not even a dyno. With the gauge, you can record lambda in all real-world driving conditions. I was able to determine that a 120 main is too rich and a 115 is slightly lean. I now run a 117. :)

I just ordered my own Innovate Motorsports setup...
 
Photos from Carl

With many thanks! ....

All in 1 photo... (big enough to print a decent page)
x19airfuelcurvesm.jpg
 
Nice reference graphs!

Narrow band is useless for tuning, as stated above, it just doesn't read in a range to be meaningful for adjustments.

Get a wideband kit, I use AEM on my wagon

XC4thGear.png


& datalog via an Innovate SSI-4 & OT-1 (for OBDII) to get logs such as this...

Picture4-1.png


which can be transferred to excel...

Picture6.png


.. very useful for making fuel & timing adjustments - it's hard to do it just by watching the meter alone.
 
I disagree

Wide band is supposed to be better and costs a lot of money. Narrow band 02 sensor is inexpensive and almost everyone has a digital volt meter. I have been using my set up for years and it works just fine. Especially considering I'm tuning Fiat motors that are in good but not blue-printed condition and Webers that are 20 to 30 years old. This is hobby level tuning, not some clown with Megasquirted motor with distributorless ignition and individual throttle body injection, having his buddy in the passenger seat "tune" the motor from his laptop.
This is the same kind of mindthink that said dual Weber IDFs on a stock 124 motor would never work right....which turned out to be totally bad info although in theory might sound right.

I apologize, maybe too much coffee this morning....got a buzz going.

Carl...single band in Virginia
 
carl said:
I apologize, maybe too much coffee this morning....got a buzz going.

Carl...single band in Virginia
Click to expand...

haha.. let me join in then.

I SHOULD be running a wide band system, but its not in the budget at the moment. I'm happy with a narrow band system because its cheap confirmation for other things that are happening correctly. As long as it stays on the rich side I'm not going to melt the motor, and thats fine for me right now. I applaud folks for investing in the wide-band kit to fine tune their car, I should do that too, maybe in the near future,

Don't disregard narrow-band kits completely. They look cool, keep me from melting a piston(cheap insurance), and look especially rice which goes with my coffee-can exhaust.

Also, don't forget the old EGT gauge, which old school folks have been using for years.

Byt the way, using a volt meter as an a/f meter is rediculous when you can buy a $10 gauge on ebay...but great info here..love that chart on narrow bands, thanks!
 
Target fixation

I had a cheap A/F guage on one of my Fiats built into the dash but found I kept staring at it....instead of the road. I only need the gauge to check jetting, not as a constant readout device. I already had the volt meter so that's cheaper than the $10 ebay gauge!
 
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