No Cat, No Oxygen sensor.

[Spyda]

Ive read on Vortex that you can use just about anything. People use ford o2 sensors as they are about one third the price of a digi mk2 sensor.

Are you sure your ECU is digi 2?

I know you can use a mk3 sensor on a mk2, the forth wire is just an extra earth, the rest is the same.

[ryana89]

I am fairly certain that its a Digi 2 unit.
On top of the ECU it states that it is Bosch (of course) and Digifant, but it also has the code "DF1" on the sticker/label.
And according to wiki, that was the ECU module used on Cabrio Golfs with a 2E engine. (do I trust wiki)

Keep in mind I dont have a standard Mk2 and that my O2 sensor harness is a 4 wire one. (Apparantly similar to a MK3 one)
Could sombody link me up with an explanation on how Generic O2 sensors work? I understand how an O2 sensor works, but I don't see how one not intended for a car is going to do anything but send the wrong signals (Ie to lower voltage or to higher voltage).

Thanks

[ryana89]

Ok, its been a while but I've done the rounds with a few other Auto sparkies in the town.
I asked them "how do you recognise a 4 wire oxygen sensor plug if you're uncertain if it is one and how would the voltage/resistance act?", then "If you can identify which wire does what, can you hook the wiring up for me?".

I went to a (trusted) Auto Electrican who, was willing to have a look over of the car and actualy speak with me, but he said he would not be able to definativly connect the 4wire O2 sensor that I have without wiring diagrams. Ok, atleast he came out to my car and spoke with me.

Next was a man with experience with German/European cars, I asked the same questions again and he would not discuss the topic at all with me, stating "If I gave you advice, you'd probably forget it....". Mate, not the question I asked, I simply wanted to know if he could do the job or not. He wanted $$ before answering anything.

Can anyone here offer advice on voltages/resistance on a 4 wire oxygen sensor? The 2 white wires are for heating, the grey wire is earth and the black wire is a signal wire on the O2 sensor. What 'signal' would the ECU send down these wires that can be measured with a Multimeter.
Keep in mind the plug in the engine bay has 4 wires of the following colours Green/Red, Yellow, Brown, White/Blue.

Thanks.

[peedman]

Mate its really hard to confirm what goes to what because your wires are different colour to mine. On my desk here i have an ibiza cupra connector and they are

#1 - Red/white
#2 - Brown/black
#3 - Green
#4 - Black (which is definately the signal)

I can tell u that on the o2 sensor plug for a mk3 or ibiza that pin #4, which is the pin separated by a tab, is always the o2 signal wire. It can be different colours tho depending on the year.

You should try and decifer from these links, i had a look but i cant confirm anything.

Motronic Pinout
Fusebox FAQ - Club GTI
Installing an Air Fuel Ratio Gauge

Btw did u end up buying an o2 sensor? Ive got a spare (used) one like the from gap that i can send u if u pay for postage

[ryana89]

I understand the difficulty trying to diagnose problems over the internet, but hey you've helped me out more than the 'professionals' I've met so far.
The MK3 Ibiza ran a 2E with Digi 2 didn't it?

I went through another of the wiring/colour charts on the A2 resource website and no colours match up at all!

I did end up buying a MK3 o2 sensor with the spacing/tab between wire #3 and #4 (not the one I wanted of course).


Let me see If I can clarify things with some more infomation
(Assume)

#1 - Green/Red
#2 - Yellow
#3 - Brown
#4 - White/blue



With engine running and a multimetre set up so that positive needle on multimetre is on the positive battery terminal.

Negative needle goes on the following wire's, results/voltages shown.
#1 -8.5 volts
#2 - 2 volts
#3 - 0
#4 - 0

When positive needle is placed on #2 and negative needle placed on #1 - 6.4 volts is shown.

This is with the engine still cold and at idle.
Chances are that information wont help at all but you never know

Thanks

[ozvino]

Ryan, isn't your car Sth African? Have you tried anyone in Sth Africa?

Maybe email these guys and ask the question; Google is your friend........

Volkswagen Engine Installations & Upgrades | Johannesburg

Dave

[peedman]

When you say that u found this plug near the 4th cyl runner do you mean on the passengers side or the drivers side? Just trying to clarify because the cylinders are 1 2 3 4 when looking from the front of the car so the 4th cyl would be on the passengers side. The o2 sensor plug is normally found on the drivers side.

Other than that i cant really help you. Ive looked it over and over and each time i reach a conclusion i realise i am wrong and get more confused.

If i were in your position i would wire it up as you see it i.e. like the mk3 plug and see if it works. After all there are only finite number of possibilities!

[ryana89]

Certainly is a South African car.
There are no details (in the service books) about where/when the 2E was converted into it, I only have the address from where it was first sold (which is now a car rental place).

I've been googling since the day I bought my car
Unfortunatly this is the only question I cant find an answer too

[ryana89]

When you say that u found this plug near the 4th cyl runner do you mean on the passengers side or the drivers side? Just trying to clarify because the cylinders are 1 2 3 4 when looking from the front of the car so the 4th cyl would be on the passengers side. The o2 sensor plug is normally found on the drivers side.

Other than that i cant really help you. Ive looked it over and over and each time i reach a conclusion i realise i am wrong and get more confused.

If i were in your position i would wire it up as you see it i.e. like the mk3 plug and see if it works. After all there are only finite number of possibilities!

Yep, on the 4th intake runner closer to the passenger side.
I'd hapily hook the system up, but I'm worried if I wire it wrong, I could do damage to the, rather rare, ECU.
I cannot think of what else this plug could be for, and thats why I'm assuming its for an o2 sensor.

If I can't figure this out, my only option is to drive to Sydney and see Loon.
I wonder how easy a K-jet conversions is......

[peedman]

Having spent the good part of today sorting out my wiring harness i tend to agree with u that its for an o2 sensor. I dont recall any 4 plug harness in the engine bay other than the o2 sensor if anyone else can chime in. It just happens that urs is located in a different place than the usual!

I wouldnt do a kjet conversion as you would be going back a step from efi. Have u scanned the car for any codes btw, that would be a good idea and should bring up any fault codes.