AE86 Oxygen Sensor help...

[Ian.G]

Hi guys,

trying to understand a little more about my hachi.

When I installed my T3 test/decat pipe this is what I removed.



as I understand it this is a catalyst heat probe. I believe this is only used to turn on a light on the dashboard if the catalyst breaks down and starts to overheat.

I have an o2 sensor in one of the primaries in my exhaust manifold (excuse the poor picture - it was dark)



This sensor has a single wire running from it. If I follow the wire I find its plugged into ..... wait for it ..... nothing. :o

Can anyone suggest where this *should* be connected to on the loom ?

I assumed my Freedom ECU would still be using the o2 sensor for cruise/part throttle and then not use it when the computer sees full throttle/closed loop.

Anyone have any suggestions ?

[Aico]

LOL!!

I don't know about the Freedom ECU, but it probaly works without the O2 sensor. Most aftermarket ECU's do this. They just look at the MAF or TPS to see howmuch fuel needs to be injected. There is no need to check the stock O2 sensor since you already fully tuned the ECU and a narrow-band isn't very precise..

A wide-band O2 sensor does have a function with programmable ECU's, but you got the stock sensor.

[dreja]

Just wondering:

My car has a screw in one pipe of the exhaust manifold (is this o2 sensor? ), as seen on the picture.


Does this tell that my car should have also the catalytic converter?

I'm asking this because I've bought the car with changed exhaust pipes and I'd like to avoid problems when doing every year's a MOT test.

Regards
Andrej

[NoHachi]

The freedom ecu does run closed loop during most circumstances, so the stock O2 should be plugged in...

The more I read about all these little things that are wrong with your car, the more I am convinced that you are one lucky bastard. The engine could have blown any time if even the ecu has no clue as to what the AFR is.
The only thing i can come up with is that someone tuned this thing for the track. That would mean running it in TPS mode, which is not really suited for closed loop operation. That would also mean that you should at least have to upload a MAP basemap before you can start running closed loop. Any way in which you can check the mode the ECU is running in?

I would check these things first. It could be a matter of just plugging the sensor in, but might as well make sure.

[Ivan141]

@Dreja:
That plug is not supposed to be there on most european models I think. It looks like there was an EGR pipe connected to it before.
I'm pretty sure that the O2 sensor usually sits lower on the downpipe because it would only measure the A/F ratio of one cilinder if it's that high on the manifold.

[JonT]

@dreja

that bolt attaches a heatshield over the top of the manifold, nothing to do with oxygen sensors.

edit> nope, wrong i'll look more closely next time

Did European cars come with cats ? I know Japanese imports like Ians do, but UK cars were cat free

[Ivan141]

Ehmm...that huge bolt there is certainly not for the heatshield..
The position of it looks exactly like the mounting point of the EGR pipe on the manifold of an AE92 4AGE manifold. The bolt is about as big as the oil drain plug.

[robokill]

hmmz standard euro hachi's didn't come with cat or anything like it all.

Ian i think its time you start thinking of serieusly learning JAP to get the freedom ECU working correctly this could get messy and all the stuff you find i would remove it all when you got to understand the ECU and then rebuild en reprogram caus its seems a mess over there

[Aico]

Learning to speak Japanese is realistic, but learning to read and write Japanese is

Maybe you can get a Jap->Eng translator? I mean a real translator near you.

[dreja]

The bolt isn't for heatsheld, there is a metal tube going from under the bolt to intake manifold. It should be EGR system, like Ivan said...

I've checked in Toyota EPC program, that my car didn't came with catalytic converter, because it was for swiss & sweden market. If it were for the german market, there will be also a cat. converter...

Andrej