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st184 Air Fuel Ratio Gauge difficulties


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#1 Brad68

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Posted 24 January 2011 - 12:19 PM

So i bought an air fuel ratio gauge from Supercheap Auto on the weekend

http://www.superchea...=155249#details

I wired it all up and tested the gauge with just a temporary connection into the O2 sensor wire in the engine bay. Everything worked but the gauge was jumping around all over the place... I've read about this occurring without using a "wide band sensor" or something?

I was thinking to maybe try and piggy back the wire to the one that goes into the ECU but thinking now maybe this wont even make it perform any different?

Can anyone tell me if i need a wide band sensor (despite the site saying it uses narrow band, i think...)
If there is a wide band sensor that comes standard in a celica st184 anywhere?
If plugging it into the ecu will help the issue?

or what i should actually be doing...

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#2 mick.wheelz

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Posted 24 January 2011 - 12:54 PM

So i bought an air fuel ratio gauge from Supercheap Auto on the weekend

http://www.superchea...=155249#details

I wired it all up and tested the gauge with just a temporary connection into the O2 sensor wire in the engine bay. Everything worked but the gauge was jumping around all over the place... I've read about this occurring without using a "wide band sensor" or something?

I was thinking to maybe try and piggy back the wire to the one that goes into the ECU but thinking now maybe this wont even make it perform any different?

Can anyone tell me if i need a wide band sensor (despite the site saying it uses narrow band, i think...)
If there is a wide band sensor that comes standard in a celica st184 anywhere?
If plugging it into the ecu will help the issue?

or what i should actually be doing...


You are using the ****ty narrow band sensor the car comes with, this will *not* give you any sort of accurate idea of your AFR's

You will need to purchase a wideband O2 kit if you wish to measure AFR's

I would go with either a Innovate or Zeitronix kit (I actually own the Zeitronix one, its not bad)

http://www.innovatemotorsports.com/
http://www.zeitronix.com/

#3 Brad68

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Posted 24 January 2011 - 01:07 PM

Here is a vid of the gauge bouncing...


#4 Brad68

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Posted 24 January 2011 - 01:08 PM


So i bought an air fuel ratio gauge from Supercheap Auto on the weekend

http://www.superchea...=155249#details

I wired it all up and tested the gauge with just a temporary connection into the O2 sensor wire in the engine bay. Everything worked but the gauge was jumping around all over the place... I've read about this occurring without using a "wide band sensor" or something?

I was thinking to maybe try and piggy back the wire to the one that goes into the ECU but thinking now maybe this wont even make it perform any different?

Can anyone tell me if i need a wide band sensor (despite the site saying it uses narrow band, i think...)
If there is a wide band sensor that comes standard in a celica st184 anywhere?
If plugging it into the ecu will help the issue?

or what i should actually be doing...


You are using the ****ty narrow band sensor the car comes with, this will *not* give you any sort of accurate idea of your AFR's

You will need to purchase a wideband O2 kit if you wish to measure AFR's

I would go with either a Innovate or Zeitronix kit (I actually own the Zeitronix one, its not bad)

http://www.innovatemotorsports.com/
http://www.zeitronix.com/



Ahkk fantastic cheers! Ill get onto that and let you know how i go

#5 Brad68

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Posted 24 January 2011 - 01:51 PM


So i bought an air fuel ratio gauge from Supercheap Auto on the weekend

http://www.superchea...=155249#details

I wired it all up and tested the gauge with just a temporary connection into the O2 sensor wire in the engine bay. Everything worked but the gauge was jumping around all over the place... I've read about this occurring without using a "wide band sensor" or something?

I was thinking to maybe try and piggy back the wire to the one that goes into the ECU but thinking now maybe this wont even make it perform any different?

Can anyone tell me if i need a wide band sensor (despite the site saying it uses narrow band, i think...)
If there is a wide band sensor that comes standard in a celica st184 anywhere?
If plugging it into the ecu will help the issue?

or what i should actually be doing...


You are using the ****ty narrow band sensor the car comes with, this will *not* give you any sort of accurate idea of your AFR's

You will need to purchase a wideband O2 kit if you wish to measure AFR's

I would go with either a Innovate or Zeitronix kit (I actually own the Zeitronix one, its not bad)

http://www.innovatemotorsports.com/
http://www.zeitronix.com/


Ok so wow.. the prices arent quite what i expected.. i was told it was an easy and cheap install for these sensors.. sigh :S

Do i need the whole kit? what if i got just the sensor, eg something like this?

http://cgi.ebay.com/...es#ht_534wt_962

or

http://cgi.ebay.com/...s#ht_1588wt_804

could i put the sensor in and just connect the wire from my gauge into that? (assuming the sensor is standalone not needing any kind of power or anything from what I've seen on youtube with gauge demos...)

with that, would i be able to replace the current sensor with this wideband one or would i need to keep the original one in place and wired up as well?

#6 mick.wheelz

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Posted 24 January 2011 - 03:01 PM

The sensor will require the control hardware (e.g the ZT-2 or 3 for the Zeitronix) to function correctly.

A WBO2 is not a cheap device, is it something you actually need? e.g will you be modifying the motor in such a way that you will need to monitor AFR's

If you buy a kit, some of them can emulate the narrow band (for the ECU), so you can remove it (this is how he one in my ST184 is setup)... as for the gauge, the cheap ones that use a narrow band are basically useless.

#7 Brad68

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Posted 24 January 2011 - 04:00 PM

Nah won't be doing much to the 5s.. However the current o2 sensor wire is kinda fried (fell hanging down against the manifold) so could probs do with replacement at some point anyway haha. Still connects and all, just is in a bad way. If there's wb sensor that can replace the standard sensor and connect into the ecu, I reckon that'll be the way to go eventually. When I actually do it is another question.

But, in preparation for when that happens, exactly what model wbo2 kit should I be getting (to ensure I get one to replace the current setup)? And secondly, where in the car do I find the ecu? Haven't managed to get a straight answer for that yet.. If you have a diagram of the ecu pinout as well I'll be 100% set

Thanks a heap for all your help!

#8 mick.wheelz

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Posted 24 January 2011 - 05:14 PM

Nah won't be doing much to the 5s.. However the current o2 sensor wire is kinda fried (fell hanging down against the manifold) so could probs do with replacement at some point anyway haha. Still connects and all, just is in a bad way. If there's wb sensor that can replace the standard sensor and connect into the ecu, I reckon that'll be the way to go eventually. When I actually do it is another question.

But, in preparation for when that happens, exactly what model wbo2 kit should I be getting (to ensure I get one to replace the current setup)? And secondly, where in the car do I find the ecu? Haven't managed to get a straight answer for that yet.. If you have a diagram of the ecu pinout as well I'll be 100% set

Thanks a heap for all your help!


It depends what you want to do, I myself have the Zeitronix ZT2 Wideband kit (http://www.zeitronix...s/zt2/zt2.shtml) and it does work very well.

However, innovate's kit can do some cool shit such as iPhone intergration, etc, etc (http://www.innovatem...39&cat=0&page=1)

As for the ECU, it is located behind the stereo, but mounted towards the firewall and down low.

The easiest way to access it is to pull up the carpet on the passenger side, you can then unplug the loom.

What year is your celica, I can then provide a wiring diagram to suit.

#9 Brad68

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Posted 24 January 2011 - 09:38 PM

Alrightey. Ill have a little think about the plan of attack.

Celica is a 92 sx,

thanks again for everything!

#10 Brad68

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Posted 25 January 2011 - 08:05 AM

just an observation, i put a multimeter to the o2 sensor last night to see what it was putting out, and found it bouncing between about 1.5-4.5v :S wideband range right?

also, long shot i know, but since the gauge is now just sitting looking pretty, what are the chances do you reckon there is something else with similar signal strengths i could bridge it into for now just to make it do something haha e.g. i was thinking the MAF sensor? or would it more likely be everything else runs different voltages/signals? (couldnt get the multimeter in there myself)

#11 mick.wheelz

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Posted 25 January 2011 - 09:02 AM

just an observation, i put a multimeter to the o2 sensor last night to see what it was putting out, and found it bouncing between about 1.5-4.5v :S wideband range right?

also, long shot i know, but since the gauge is now just sitting looking pretty, what are the chances do you reckon there is something else with similar signal strengths i could bridge it into for now just to make it do something haha e.g. i was thinking the MAF sensor? or would it more likely be everything else runs different voltages/signals? (couldnt get the multimeter in there myself)


a wideband is *meant* to be 0-5v, with that said when was it changing voltage? just randomly or otherwise?

newer narrowband o2 sensors do operate in a wider voltage range, and are heated for (somewhat) more accuracy, but regardless they are no-where near as accutate as a WBO2.

#12 Brad68

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Posted 25 January 2011 - 10:11 AM


just an observation, i put a multimeter to the o2 sensor last night to see what it was putting out, and found it bouncing between about 1.5-4.5v :S wideband range right?

also, long shot i know, but since the gauge is now just sitting looking pretty, what are the chances do you reckon there is something else with similar signal strengths i could bridge it into for now just to make it do something haha e.g. i was thinking the MAF sensor? or would it more likely be everything else runs different voltages/signals? (couldnt get the multimeter in there myself)


a wideband is *meant* to be 0-5v, with that said when was it changing voltage? just randomly or otherwise?

newer narrowband o2 sensors do operate in a wider voltage range, and are heated for (somewhat) more accuracy, but regardless they are no-where near as accutate as a WBO2.


as for the multimeter reading, it was consistent fluctuating, and just at idle.
However the gauge itself when i went for a test drive, with no throttle sat needle at the bottom. Then with little to almost full throttle it was constantly and consistently bouncing back and forth between low lean to high rich (completely unrelated to throttle position, speed, load, anything...). but with fully opened throttle it would stay up in high rich.
confusing as hell.. its like theres no signal at idle, pluses of signal with throttle, and constant signal with WOT. pretty useless for the gauge though like you say haha.

might try take a vid again this arvo of a drive, but yea probs not of much use anyway?

#13 mick.wheelz

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Posted 25 January 2011 - 10:28 AM



just an observation, i put a multimeter to the o2 sensor last night to see what it was putting out, and found it bouncing between about 1.5-4.5v :S wideband range right?

also, long shot i know, but since the gauge is now just sitting looking pretty, what are the chances do you reckon there is something else with similar signal strengths i could bridge it into for now just to make it do something haha e.g. i was thinking the MAF sensor? or would it more likely be everything else runs different voltages/signals? (couldnt get the multimeter in there myself)


a wideband is *meant* to be 0-5v, with that said when was it changing voltage? just randomly or otherwise?

newer narrowband o2 sensors do operate in a wider voltage range, and are heated for (somewhat) more accuracy, but regardless they are no-where near as accutate as a WBO2.


as for the multimeter reading, it was consistent fluctuating, and just at idle.
However the gauge itself when i went for a test drive, with no throttle sat needle at the bottom. Then with little to almost full throttle it was constantly and consistently bouncing back and forth between low lean to high rich (completely unrelated to throttle position, speed, load, anything...). but with fully opened throttle it would stay up in high rich.
confusing as hell.. its like theres no signal at idle, pluses of signal with throttle, and constant signal with WOT. pretty useless for the gauge though like you say haha.

might try take a vid again this arvo of a drive, but yea probs not of much use anyway?


Probably not, going on readings taken from my WBO2, the AFR should be stable at idle (mine fluctuates arround .2 at most) meaning the signal from your narrowband seems false.

also, here is the ecu pinout
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#14 Hiro

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Posted 25 January 2011 - 10:58 AM



just an observation, i put a multimeter to the o2 sensor last night to see what it was putting out, and found it bouncing between about 1.5-4.5v :S wideband range right?

also, long shot i know, but since the gauge is now just sitting looking pretty, what are the chances do you reckon there is something else with similar signal strengths i could bridge it into for now just to make it do something haha e.g. i was thinking the MAF sensor? or would it more likely be everything else runs different voltages/signals? (couldnt get the multimeter in there myself)


a wideband is *meant* to be 0-5v, with that said when was it changing voltage? just randomly or otherwise?

newer narrowband o2 sensors do operate in a wider voltage range, and are heated for (somewhat) more accuracy, but regardless they are no-where near as accutate as a WBO2.


as for the multimeter reading, it was consistent fluctuating, and just at idle.
However the gauge itself when i went for a test drive, with no throttle sat needle at the bottom. Then with little to almost full throttle it was constantly and consistently bouncing back and forth between low lean to high rich (completely unrelated to throttle position, speed, load, anything...). but with fully opened throttle it would stay up in high rich.
confusing as hell.. its like theres no signal at idle, pluses of signal with throttle, and constant signal with WOT. pretty useless for the gauge though like you say haha.

might try take a vid again this arvo of a drive, but yea probs not of much use anyway?


The reason why an O2 sensor flickers back and forth so much on light and medium throttle is that it is running a closed-loop feedback system - the ECU is registering whether the exhaust is rich or lean and adjusting the mixture to strive to get it closer to the ideal level. However, on full throttle the ECU ignores the O2 sensor output and goes into open-loop - it just uses the fuel map for judging mixtures, which invariably leads to the engine running rich up top on WOT (hence the stable signal). This is a design feature though to prolong the life of the engine, as a lean mixture at WOT and high RPM is a very bad thing for an engine. Same goes for idle - it ignores the O2 sensor feedback and leans out the mixture to improve fuel economy during idle (no point pouring fuel in if you're not going anywhere). Thus, since a narrowband only sees 2 basic conditions (lean and rich, say 0-2V lean and 3-5V rich), you'll get constant signals at idle and WOT, and constant flickering between two levels when on part throttle. A wideband sensor will give a lot more accurate and detailed information

In short, a narrow-band tells you if it is rich or lean, a wideband tells you exactly HOW rich or lean (and tells the ECU the same thing, if you have an aftermarket unit).

#15 Brad68

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Posted 25 January 2011 - 11:16 AM

Cheers for that! I think i read somewhere that the "ox" pin is the one that goes to the o2 sensor?

secondly, yea its quite possibly fried, and keeps dropping out. no consistent readings... might be worth trying a replacement from toyota. then again, might just go the wideband kit and not waste time. would a fried o2 sensor put out the AFR and make the car run lean or rich or not really affect it?

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