I got a 4-wire O2 sensor hooked up to an air/fuel gauge (O2 sensor is Nordskog, Air/Fuel is Cyberdyne).

The air/fuel shows FULL rich all the time now, I don't know why. So I go in and try to find out what's going on. Everything is connected right (I even tried disconnecting the 2 white wires for the heating element in case there's a short.. no difference)

So I open up the wire for the signal (O2 sensor signal to air/fuel "orange" wire) and connect that to ground to see what sort of voltage it's getting. The sucker was reading TEN volts. As soon as I connected it to ground it seemed to go down slowly, eventually coming to 1 volt and LEDs started disappearing on the air/fuel gauge. I disconnecetd the voltmeter from the signal wire & ground, and the LEDs started lighting up again.

What the @#%(* is the problem with this piece?

 

Bad sensor?

 

A/F and o2 sensors are very inaccurate, unless you wanna spend the money for a wideband .

Get an EGT gauge.

 

Go here http://www.nordskogperformance.com/airfuel.html
and ask for tech support.

 

been there already, I know these things..

I'm not asking you guys your opinions on how much they suck and what else I should dump my money on. I'm trying to get what I already spent money on, to work.

 

*bump*

I need an answer on this please. Anyone with electronics expertise?

I'm wondering it might be one of a few things:
O2 sensor bad (it's brand new though)
Air/Fuel gauge bad (it's brand new too)
OR...
There's 4 wires.. 2 white, 1 black, 1 gray. The instructions say connect 1 white to switched power, the other white to ground. The Gray goes to engine ground it says (colors make no sense to me, but hey..) and the black is the signal wire (again, colors make no sense).

Is it POSSIBLE that the gray is actually the signal and what I'm seeing is the ground TRYING to ground itself through the black wire (which I'm using as the signal wire, because that's what they told me it was)?

 

O2 sensors generate their own voltage. Is your exhaust grounded? I know the factory exhausts have ground straps. Also, is your engine block grounded? Because if some of the voltage from your sparkplugs/coils isn't getting to the body, perhaps it could be using your O2 sensor wires. I would assume ground is black too. Just take a multimeter and check it with the car idling, put one prong on a good ground and the other on the grey or black wire. It should be under 1v.

 

2-4 wire sensors ground through the wire... not the sensor.

I wouldn't have bought a 4 wire... it won't help you at all. I'll buy a 2 wire next time I change mine.

 

it's just what was "in the package" that I got.. it all came basically together.

I'm going to call their tech support tomorrow.. I guess nobody else had this problem before?

Maybe I can check the voltage on the stock O2 sensor and see if that's any good.

 

some newer O2 sensors voltage rangges are 1v to 5v
the a/f gauges usally only work with 0.1v to 1 volt

 

Its actually very simple, although I dont get it why the wires are so mixed up....

anyway, you need two grounds (just strap them together, it doesnt matter), one +12V (switched-on should be better than always on) and the signal. Cannt go into color-details now without looking at the sensor and gauge myself, but it shouldnt take more than 2 minutes. Sounds like you mixed a ground with the signal though....

Easiest way to determine which wire needs to go where, is to test the Ohm resistance between the wires. When you get infinite, you dont have a connection (scratch that). You should get two values between two wires each time. The lower value (in Ohms) should be the two wires used to measure the signal (smaller resistance), so the other two wires should be the ones used to power the sensor and gauge. Which ones you connect to ground shouldnt really matter as well....

 

Send those back - they are junk - I've been there. Get this instead.
http://www.techedge.com.au/vehicle/wbo2/default.htm

 

This one runs from 0 to 1 volt (the manufacturer said so)

I'll try the resistance method.

I'm not going to make my own kit (and/or spend money on something AGAIN) I already covered this in a previous post.

 

Brainfart! I bought a 4 wire sensor a while ago, and I grounded it to the battery. The sensor worked fine compared to the 1 wire sensor for me. Barwick, where did you ground the sensor? Did you try using the black as the ground and the grey as the Signal? I had a nordskog (?) O2 sensor and gauge, and the grey was the signal I believe.

Man... when you get it working, your car will be Fast and Furious!

 

I'm going to kill you.

Anyhow.. I called Nordskog and they said the black IS the signal. I think that's completely bass ackwards, but anyhow...

I disconnected it and re-re-rewired it and now it shows 0 voltage, so I'm going to have to check the wiring elsewhere AGAIN.. I hate cars sometimes.

 

I hooked the 4-wire into my ECU (the original O2 sensor was shot) and the air/fuel gauge did the same thing. So I was thinking something might be messed up going to the ECU, and it might run lean or something.. so I cut that wire (going from the O2 sensor to the ECU) and left the O2 sensor hooked up only to the air/fuel gauge, and now the sucker works.

AND once the check engine light comes on, the air/fuel guage shows about 14.7 air/fuel ratio at cruise It sits about 7 or 8 LEDs up under acceleration, and then goes down to 0 LED's (lean) when off throttle, then jumps back to the 7 or 8.. seems to be ok I guess.

It just seems REALLY weird that when it's connected to the ECU it doesn't display correctly at all.

 

Are you using shielded wiring? Sounds similar to my boost sensor problem. 7 or 8 is rich. That is .7 and .8 respectively. From what I hear it should be FULL rich, which is 9 or 10 on there. Mine never got up there, but I popped my engine. You'll be losing fuel economy if you don't hook your O2 sensor to your ECU. Glad you got it fixed

Fast and the Furious!

 

I'm going to kill you again....

ANYHOW.. you say it should read full rich all the time? That makes no sense. It's reading "rich" when it's under acceleration" (7 or 8 bars, maybe 8 or 9 I dunno).

And no it's not hooked to the ECU now, because that was the "cause" of the problem it seemed.

 

DISCONNECT THE POWER FROM THE HEATING ELEMENT. (the two white wires)

The factory only heats the sensor for a minute or two on cold start. Running power to it all the time can destroy the sensor, it "burns out" internally and tries to send 12 volts up the signal (black) wire.

Just clip both white wires and ignore 'em. You don't need heated O2 for your purposes.

 

Oh, I meant under rich, not all the time, silly.

 

Okay, I mean under WOT. I'm painting my engine bay... fumes.... ugh

 

um.. then why do they even sell heated O2 sensors?

 

SOME CARS use the heat element. It takes a minute or two for the O2 sensor to heat up by itself. OEMs that use heated sensors heat them for a few minutes to get them up to temp.

It's actually not uncommon for heated O2s to fail like that even in stock form. Causes all sorts of drivability problems...