How would I wire it up?

 

well you would need a sensor first because you can't make that and then a power source from a computer reading the current to ground. I think the computer making part would be the hardest.

 

Computer? Are you talking about a computer chip or a laptop kind of computer? Basically, I want to make this , but have the LEDs in a strait line. BTW, I already have an O2 sensor.

 

Hmmm well they make a kit like that all you need to do is take it apart and take the guts and hook them up to your own straight line of LEDs from radio shack. And the little computer/logic module that comes with the kit, just wire it in. But yes you will have to buy a kit and mod it for your needs because the solid state parts you can't find or make. Do you have a carb car that your trying to set up because if you have a fual injection car it won't show anything but one LED all the time because you can't change it manually on a fuel injected car.

 

My engine is a 350 TPI. I'm just trying to make it, cheaply, so that I can see what the ratio is. From there I can change up my AFPR.

 

First don't waste your time trying to tune with the stock NB O2 sensor. It's only good at 14.7 AFR. You need a Wide Band O2 to do any serious err... accurate tuning. You can build a good WB for around $200. See www.diy-wb.com for a good WB kit. You will be happy you did. cheers, Bob

 

Well 14.7 to 1 ratio is what the computer trys to maintain when in closed loop. NO need to build something to see something you already know on paper. If your O2 sensor is fairly new then thats that.

 

Hmmm, guess you don't mind buying engines then... First the stock O2 is only good at 14.7 any deveation above or below and it cannot read the AFR. Having a WB O2 to read the actual AFR and doing plug cuts is the correct way to tune. Trying to tune with just the stock NB O2 is like pissing in the wind. Its gets the job done but your all wet. cheers, Bob

< EDIT > Read this post and find out why using the stock NBO2 is just wasting time.

https://www.thirdgen.org/techbb2/sho...ighlight=NB+O2

 

For what its worth here is the typical output of a NB O2.

 

How the hell you going to tune a fuel injected car with out changing the prom?????????????? Just wondering

 

Actually, I was just goning to make it for the learning experience, and to have it if I ever do buy the equipment to burn proms.

 

I was answering the original question, that trying to tune with the stock NB O2, and a AFPR is a waste of time. A WB O2 will make tuning the prom easier, and more accurate. Its a given that the prom will need editing, however having a WB O2 and doing plug cuts is the correct way to get the data to make smart changes.
I myself have probibly one of the most odd combinations to have. Running a 749 ECM with modified $58 code on a TPI with a Eaton blower. If you really want to know whats going on, sift thru the actual source code for your application, you get a very good understanding of why the ECM is doing what, why and when. cheers, Bob

 

I built a couple of those NB o2 guages and have one in my overhead console inplace of the "trip counter". It's behind dark lexan and I use it to tune and keep watch of things like an HUD of sorts. If there is any WOT I do NOT want to see it go lean anywhere from just off idle to redline! This is my verification. The NB o2 sensor is good for that and that alone. It'll tell you if it's rich or lean from stoich (14.7), just not by how much .
I think it's a good idea to build the circuit if you've got the time. It's REALLY cheap to build, very simple, and if nothing else, just a good old electronics lesson.
Oh yeah, and I still can't afford a wide band o2 sensor even though my board has been assembled since the 1st day it arrived in the mail . I'll eventually get it when I get a better job at school instead of working for crappy Lowe's Home Improvement as a damn cashier. Just imagine this; a 6'4" OSU mechanical engineering student working as a cashier at a hardware store for $8.50 and not being allowed to leave the register to help somebody load or get something off a shelf!!!! It's DUMB, STUPID, every other ignoramous word imaginable. Oh yeah, and then they wanted me to drive 110 miles to another store each day, hahahaha, Ill NEVER be able to afford the actual sensor if I keep working for them. Me every Thursday evening, "wow, now I'll just go deposit this so I've got gas and food money for next week!" Sorry, had to vent.
Anybody have an extra wideband o2 sensor they would let me borrow JUST to see if my board works? I can wish can't I.

 

The question still remains; how do I build it?

 

http://diy-efi.org/diy_efi/projects/O2_LED/O2_LED.html

or....
http://www.students.tut.fi/~eppu/dev/EGO-bar.html

 

Why not just put the cars ECM in the field service mode? With the engine running and at temp jump terminals A+B same as you would to retrieve codes. A rapid flash rate from the SES light(approx 2 and half times sec) indicates open loop, slower (1/sec)will indicate closed loop. If running lean in closed loop the SES will stay off for most of the cycle, rich it will stay on for most of the cycle time. Problem with trying to monitor voltage from an O2 sensor is that the voltage is always bouncing around so it must be averaged. Also most inexpensive voltmeters input resistance are too low and it simply loads down the sensor and in some cases will destroy it. The meter must have an input impedance of 10Mohm's or greater. I use an oscilloscope with storage features, however I realize most people don't have access to that. If the ECM is working and the O2 is good the ECM will take care of the rest.

 

WHY NOT DO THIS BUY A GUAGE IN SUMMIT AND ONE WIRE GOES TOO POWER AND THE OTHER ONE FEEDS OFF THE O2 SENSOR,IT WORKS GOOD ON MY CAR NO PROBLEMS...

 

First off your caps lock is stuck so get a new keyboard. Secondly the o2 gauge circuit has got to be the 2nd easiest thing to build (first has got to be the winaldl 2 resistor 1 transistor interface). For only $6 in parts and 15-30 minutes of your time you could build your own gauge that is ADJUSTABLE!!! Yes, you heard me right. You can adjust the resolution that is to be displayed. Example; 450mv is dead center on the LED bar and 350mv is no LEDs while 550mv is all bright OR you can have it so that 100mv is dark and 900mv is all lit up. Oh yeah, and you can adjust if you want them to light up in either "bar" or "dot" mode. Ah, almost forgot...you can adjust the brightness . So figure those 15-30 minutes plus time to get the parts vs sitting on your **** waiting 2 to 3 days for your overpriced gauge to come to your door .
Anywho, I wanted my gauge up in my overhead console behind tinted lexan (which is finally complete) and having the 10 LED bar to remotely mount away from the circuit board was an added bonus. I would have spent more time taking apart a pre-made then I did building this one from scratch.

 

YAWN

 

Considering I have absolutely NO electriacal experience, as fun as it would be to make my own O2 gauge, those pages you linked to to make one, dont help me at all its like reading a different language. Unless there is a better visual simplistic example of building one out there I think I will stick with buying one off summit.