Identifying a O2 Sensor wiring on 20V SVT

[olskool]

Hi all,

Pls help, I'm a bit confused coz I got myself a new O2 sensor and the wires are :-

1 white (signal earth)
1 blue (signal)
2 black (heater)

my current O2 svt stock has got :-

2 black
2 grey

before the socket, a totally different set of wire colours :-
1 Big grey wire join to a black wire to the socket
1 Pink black
1 Red Black
1 Black red

Can anyone teach me how to connect my new O2 sensor to the old wiring? Pics below..

Thanks in advance..

 

[hky91]

waiting for an answer too!

 

[levin818]

olskool,
Is this your current connection?

O2 --> Hardness --> ECU
black --> pink black --> HT
black --> black red --> +12V (IG SW)
grey --> black/big grey --> OX
grey --> Red black --> OX+

---------- Post added at 02:01 AM ---------- 6 hour anti-bump limit - Previous post was at 01:26 AM ----------

This may helps:
http://www.zerotohundred.com/newforums/toyota/315180-o2-wiring-need-help.html#post4033229

 

[olskool]

Hi Sifu wong,

Yes it was but since I bought the new O2 sensor, it only has :-

1 white
1 blue
2 black

So my questions is which wire from the harness goes to the new O2 sensor (pic below)? Thanks.

 

[levin818]

O2 --> Hardness --> ECU--> New O2
black --> pink black --> HT --> black
black --> black red --> +12V (IG SW) --> black
grey --> black/big grey --> OX --> White
grey --> Red black --> OX+ --> Blue

For SVT, the ECU sense the low side signal (signal earth) of the O2 sensor.
Therefore, white wire should be connected to OX.

 

[cuscostrutbrace]

Sifu,isnt that the OX is blue and OX+ is white? confused,i need to look back at my car..

Olskool,if you have multimeter you can check the O2 functions or not,i think in Chinozie blog there is a how-to bout this (taken from sifu Levin818)

 

[levin818]

The pin description for O2 sensor in SVT and BT are diff. However the functioning concept are similar.
Imagine the O2 sensor is like an AA battery which has (+) and (-) terminals. The voltage across these 2 terminal will varied according to the oxygen contents in the exhaust.

For SVT, the ECU tide (+) to reference 1V, and read the signal changes at (-).
O2 --> ECU --> Description
grey --> OX+ --> connected to reference 1V
grey --> OX --> main chip read the voltage changes at this pin

For BT, the ECU fix the (-) to earth, and read the signal changes at (+).
O2 --> ECU --> Description
blue --> OX --> main chip read the voltage changes at this pin
white --> N/A --> connected to earth (reference 0V)

So how to connect the O2 sensor is depending on what type of ECU you are using.

 

[cuscostrutbrace]

The pin description for O2 sensor in SVT and BT are diff. However the functioning concept are similar.
Imagine the O2 sensor is like an AA battery which has (+) and (-) terminals. The voltage across these 2 terminal will varied according to the oxygen contents in the exhaust.

For SVT, the ECU tide (+) to reference 1V, and read the signal changes at (-).
O2 --> ECU --> Description
grey --> OX+ --> connected to reference 1V
grey --> OX --> main chip read the voltage changes at this pin

For BT, the ECU fix the (-) to earth, and read the signal changes at (+).
O2 --> ECU --> Description
blue --> OX --> main chip read the voltage changes at this pin
white --> N/A --> connected to earth

So how to connect is depending on what type of ECU you are using.

So....Blue is connected to OX pin and white is connected to the ground for BT O2 sensor right.

Both SVT and BT O2 sensor is different in nature.They are not the same,but their objectives is the same.

SVT O2 sensor is Titania based.It will varies the resistance according to oxygen difference reading.The OX+ pin from the ECU feeds constant 1V to the sensor,the sensor then varies its resistance accordingly,and the ECU OX pin will measure the voltage output from the sensor after the resistance.This type of sensor is like a variable resistor.It does not produce its own voltage hence it needs constant voltage feed.

The BT O2 sensor is Zirconia based.It does not need voltage feed to it as it produce its own voltage.Hence the BT ECU does not have the OX+ pin.One of the sensor is connected to ground and the other one is connected to ECU pin OX (O2 signal input),which will measure the voltage coming out from the sensor.

So,what if we use SVT O2 sensor with BT ECU? Since the BT ECU does not have OX+ pin,so there is no voltage feed to the O2 sensor, how the sensor can produce output voltage without the voltage feed right? . So for those who convert from SVT to BT ECU,it is advisable to change the O2 sensor to BT as well,due to this difference.

What d u think?

 

[chinozie]

Levin818 - Right on...is the wiring connection works ?

Here's some of the pin connection picture :

1 - grey -> black / thick grey
2 - grey -> red black
3 - black -> pink black
4 - black -> black red


cuscostrutbrace - Would agree that...cuz last time, my old wiring...I went to Angah, try to install an A/F ratio meter...BT wiring with SVT O2...plug in the A/F ratio meter...the thing didn't show anything...so Angah decide to adjust the wiring...

After a while, he fail to pull it out...then decided to swap with BT O2 Sensor...Vualllaaa...!!! The A/F ratio is alive...

Now the explanation you gave, it might be the brief idea why it wasn't working at first place...perhaps...

 

[cuscostrutbrace]

Levin818 - Right on...is the wiring connection works ?

Here's some of the pin connection picture :

1 - grey -> black / thick grey
2 - grey -> red black
3 - black -> pink black
4 - black -> black red


cuscostrutbrace - Would agree that...cuz last time, my old wiring...I went to Angah, try to install an A/F ratio meter...BT wiring with SVT O2...plug in the A/F ratio meter...the thing didn't show anything...so Angah decide to adjust the wiring...

After a while, he fail to pull it out...then decided to swap with BT O2 Sensor...Vualllaaa...!!! The A/F ratio is alive...

Now the explanation you gave, it might be the brief idea why it wasn't working at first place...perhaps...

Well,it is because of the different sensor type.I know this when i do my SVT to BT conversion years back,so when i'm doing SVT to BT conversion for my 'customers', i always mod the O2 wire to suit BT O2 sensor and advice them find the sensor,although the engine runs ok without it.

The O2 sensor have huge effect on fueling,as it is related to closed loop and fuel trims over time.So for those who find the SAFC keeps 'reset' back,disconnect your O2 sensor,hehe

 

[levin818]

cusco,
Have you done any SVT --> BT conversion which successfully running with SVT O2 sensor?
I thought both SVT and BT sharing same O2... (Titania)?

Chin,
Tks for the pic. It make things a lot easier.
But the pin orientation has something wrong le. Black/thick grey should go to pin no. 3 right?

 

[chinozie]

cusco,
Have you done any SVT --> BT conversion which successfully running with SVT O2 sensor?
I thought both SVT and BT sharing same O2... (Titania)?

Chin,
Tks for the pic. It make things a lot easier.
But the pin orientation has something wrong le. Black/thick grey should go to pin no. 3 right?

Correct me if i'm wrong ler...

SVT (O2 sensor) -> BT (harness)

1 - grey -> pink black
2 - grey -> red black
3 - black -> black / thick grey
4 - black -> black red

 

[cuscostrutbrace]

cusco,
Have you done any SVT --> BT conversion which successfully running with SVT O2 sensor?
I thought both SVT and BT sharing same O2... (Titania)?

Chin,
Tks for the pic. It make things a lot easier.
But the pin orientation has something wrong le. Black/thick grey should go to pin no. 3 right?

Succesfully running yes..but succesfully running like factory,i guess not if still using SVT O2 sensor. But almost all of them still using SVT O2 sensor,because it is hard to find BT O2 sensor and quite expensive,so most of them happy without the sensor,since the car runs fine,with acceptable fuel economy and better response compared to them using SVT ECU. And strangely,none of them complaining the check engine light comes out.

Our factory ECU is built with high tolerance,it still can work without certain inputs,like the O2,VSS,Air temp,Water temp,Knock..the engine still runs,but not to the optimum.I have seen many conversions done (usually kahwin wiring) not connecting VSS,O2 and they are fine,summore the owner says 'OK je',hehe..

SVT and BT O2 sensor is different,BT is Zirconia.Thats why BT ECU does not feed voltage(1V) to the O2 sensor,coz it doesnt need it. :-)

---------- Post added at 02:37 PM ---------- 6 hour anti-bump limit - Previous post was at 02:30 PM ----------

Correct me if i'm wrong ler...

SVT (O2 sensor) -> BT (harness)

1 - grey -> pink black
2 - grey -> red black
3 - black -> black / thick grey
4 - black -> black red

SVT 02 sensor have 4 wires,the colors are

Pink black = Heater control - connected to ECU
Black red = +12V supply (IGN)
Black/thick grey = Sensor signal output to ECU
Red black= 1V voltage supply from ECU

And if my memory is correct,

BT O2 sensor have 4 wires,the colors are

Pink black = Heater control - connected to ECU
Black or Black red = +12V supply (IGN)
White/thick grey = Sensor signal output to ECU
Brown = Sensor ground

I confirm this when i get home,i think i have one BT O2 socket with wires still attached.

 

[olskool]

Thanks for all your comments!

Didn't know that it's this complicated and there was a difference in the O2 reading for svt and bt...well than I apologize for not informing earlier that I'm using a 5sp BT Ecu with SVT harness and just got the new O2 sensor. Previously using SVT O2 sensor.

This is the only info I got from the supplier of the O2 sensor..

black -> heater
black -> heater
blue -> signal (+)
white -> signal (-)

 

[cuscostrutbrace]

Thanks for all your comments!

Didn't know that it's this complicated and there was a difference in the O2 reading for svt and bt...well than I apologize for not informing earlier that I'm using a 5sp BT Ecu with SVT harness and just got the new O2 sensor. Previously using SVT O2 sensor.

This is the only info I got from the supplier of the O2 sensor..

black -> heater
black -> heater
blue -> signal (+)
white -> signal (-)

Then it is correct that Blue is OX and white is signal ground.Just connect it that way,i already mod your wiring to use BT O2 sensor.