DIY digital a/f gauge

[wytbishop]

I stumbled upon this the other day and I've been pondering and wrapping my head around it so I think I'm going to try it.

http://www.2gnt.com/index.php?d=DVM" onclick="window.open(this.href);return false;

It is the instructions to make a digital LCD AFR display that will work off your existing narrow band O2 sensor. Now I'm no electronics expert, but basically the O2 sensor sends a voltage back to the ECU to tell it if it needs to trim or add fuel. So all this does is calibrate the digital display to give a reading that corresponds to the AFR.

The way that this guy wired the display puts the decimal at the beginning so for an AFR of 14.7 the unit will display .147. I think if you moved the wire that goes to DP3 on the display to DP2 it would show 14.70.

I'm gonna play around with it. I'll let you know.

[fowljesse]

That is interesting. I wondered why it wasn't done before. From what I understand, it's called narrow band, because it doesn't read very much more, or less than stoichiometric, so you'll see a narrow range of afr, like 14-16. < I know that's not correct, but it doesn't seem like it'll help much. It's kind of like the idiot lights, that say, "Hey, idiot, you're low on oil!". It wouldn't help much if it told you how low, by the time it's too late. Maybe the same thing can be done with a wideband.

[wytbishop]

This gauge will basically tell you when your ECU is in open loop vs closed loop. The majority of the time you should be at about 14.7:1. If you're not, the ECU is either trimming or adding fuel. This readout will tell you when that's happening.

You're right, definitely not as useful as a wideband...but it's cool and fun. IF you have a wideband you can also do this...or just buy a $60 gauge that is already set up for your wideband.

[fowljesse]

Cool. I do like knowing what my car is doing. If I didn't have MS, I would like to have all of my sensors' info available in real time.