Air/ fuel ratio trouble

[djwest85]

I just became a member here and I was wondering if someone could help me with my failed attempt to hook up a Air/ fuel ratio guage in my 94' Cobra. I've did everything with ease until I tried to find the correct wire to tie it to the o2sensor. The gauge goes crazy, green to red, red to green. It never stays in one place. The higher the rpm goes the faster it moves around from lean to rich. The only inbetween is when the light travels from side to side and has to go through to get to the other side. I just was wondering if anyone has put one of these on their 94-95 mustang and what color the wire or wires (if it's the case) are. As you all might know it has two o2 sensors. Do these have to be tied together and then wired to the guage? Thanks for the help.

 

[AznStanger3v]

im gonna tell you a secret, but dont tell anyone, or you will be in for a world of hurt.

-unless you run a wideband, your light is going to jump around. O2 sensors switch nonstop. the more voltage, itll read rich, the less, lean. it switches up and down which is what you are reading. welcome to fuel injection, itll be doing all sorts of crazy stuff. although, it should stay in an general area for a little bit, check to make sure you are tapping the right wire

-you dont have to "tie" the two upstreams together. you can read off of one.

 

[djwest85]

There are four wires on each sensor. The one i was using is the drivers side sensor. There is a Gray w/ pink stripe wire, black wire, gray w/ yellow stripe wire and a red w/ black stripe wire. I have taped into all four and got different responses from each. None of the responses were any good.

 

[Black95GTS]

What he's saying is... the digital output you are getting from the wires is just that... digital output. The O2 sensor converts the analog reading into digital then sends it off. This is no good.... digital outputs are super fast and are basically 1's and 0's... hence the light show you get.

The only real way to get a true A/F is to buy a more expensive wideband gauge which provides an actual analog output.

Adam

 

[AznStanger3v]

What he's saying is... the digital output you are getting from the wires is just that... digital output. The O2 sensor converts the analog reading into digital then sends it off. This is no good.... digital outputs are super fast and are basically 1's and 0's... hence the light show you get.

The only real way to get a true A/F is to buy a more expensive wideband gauge which provides an actual analog output.

Adam

good job on the explanation

i often find myself starting with the textbook answer and just end up changing it to "normal talk" aka lamans. BUT, i must fix some of your post, only so you can educate others better. this is mearly constructive criticism

-although to the human eye on a a/f guage, it appears digital, it isnt. It is still an analog signal (proof on an oscilloscope), its just the guage isnt able to keep up with the switching (2-5 per second) between .1v and .9v. That is how it adjusts more accurately. digital is, like you said, 1 or 0. but what if i put that into a more common zone, like the TPS. that has a variance of voltages. there isnt any converting for that. the O2 nor the computer needs to convert the signals to digital. the only type of converting would be AC to DC. i think thats what you were thinking of.

B
U
T

I still give you props, Adam. You know your stuff

 

[Stanger007]

I agree - while watching my twEECer datalogs, the narrowband O2s constantly cycle back and forth in an analog fashion. This is their normal operation.

 

[HISSIN50]

It should be:

Left side: Pin 43 at the puter (red/blk)
right side: Pin 44 at the puter (grey/blue).

You can use a switch to toggle between the two sides if you desire.

Good luck.