Help with O2 sensors 95 legacy EJ22

Hi All - My question is sorting out the O2 sensors on this car. There appears to be up and downstream connectors in the harness. One is a white square with 3 wires and the other is grey with 4 wires. Which is the up stream? I was told both sensors were the same part #, 3 wire and these will only plug into the white connector on the main harness. The grey connector is basically similar to the end on the sensor itself so there is no way they could connect together. This led me to think that I was missing an extension harness that would connect to the downstream O2. Went to the salvage yard to find one, but all the cars were 1996 or newer. I pulled the extension harness from a 96 & 97 downstream O2 but that harness only works with the white connector on my main harness.

 

So I am at a loss as to what O2 sensor I need for the gray connector or what part number for a proper extension. The main harness connector would plug into the extension and the O2 would also need to plug into the opposite end.

(Double female extension?) Any help would be appreciated as hours of internet searching has not shed any light. Of the two (white & Grey) the grey connector had a slightly longer leg away from the 3 main engine connectors.

 

This is my 1st dealing with a subaru. The engine and wiring harness were delivered to me so I never saw it in the donor car. New to the forum and Subaru's but decided to take the plunge when my son was gifted a 79 VW bus with a broken engine. Have successfully installed the 95 EJ22 using Kennedy adapters and exhaust. Created the harness thanks to video's Mick at Busaru has posted. It started right up 1st key turn. The O2 sensors are the last items I'm trying to figure out. Thanks in Advance!! I posted Pictures further down the string!!

Edited February 21, 2020 by jgilbystl
Added pictures to help identify.

My 95 has matching connectors as your parts research found.

 

Some questions. Is the donor car a USDM 95 or some other market? Is it perhaps one of the cars that were built in 94 but first sold in 95 where that state then incorrectly titles it as a 95 when it is really a 94? Do you know if the donor had an OBDII connector?

 

My 95 has the OBDII connector, but not all the sensors normally associated with OBDII. That's because 95 USDM was a transition year. It wasn't required until 96, but Subaru was making a first attempt at rolling it out, possibly before the standard was fully written. Some OBDII scanners will talk to mine, some won't The ECU looks physically like the OBDI computers from prior years, but the software on it doesn't match the older years.

 

If you research O2 sensors for a 94 do you get results that better match your connectors? Anyway, what I'm driving at is that we'll need a lot more info to figure this out.

Browser crash == double post. Edited February 18, 2020 by doublechaz

Yes, domestic market 95 automatic. It does have an OBDII connector, using it with OBD Fusion and a wifi 327 scanner. The computer has the single connector and it matched the 95 ECU pinout. Not sure of the date of MFG.

So DoubleChaz, on your 95 is the grey connector to the downstream O2 and white to the upstream? If so are you saying that a 94 downstream will have the right connector for the grey end?

My connectors are both white and the same shape and pinout. I don't recall if the downstream was on an extension, or if it is in the 5MT harness. But that could be a difference between auto and manual. Mine is from the later half of 95 as evidenced by my 3.90 final drive ratio vs. the first half of 95 being 4.11 final drive.

 

That's why I have a concern that first half of 95 may be different/ same as 94.

On the 96, the gray triangular plug was the 1st.

Trace the wires, easy to do.

 

O.

This is the Connector I'm talking about. It comes out of the main harness right nest to the white one but had a slightly longer tail approx 6 inches. It is square like the white one but "Male" like on the end of the sensor itself. 4 wire whereas the white one is 3 wire.

Osei, Thanks but are you talking about tracing the wires back to the ECU? I got the harness and engine from a salvage vehicle that I never saw and it's the 1st Subaru I've ever worked with. So it seems like this may be specific to a 95? I'm just hoping someone in the community recognizes this connector and can tell me if it goes to the up or down stream O2. Nothing I have found has an end that would connect to this.

3 main engine, white is O2, What is the gray connector at the top? Edited February 21, 2020 by jgilbystl

No , tracing back to the O2 sensor.

Factory was a triangular gray plug.

It seems that at some point the O2 was changed and a generic plug was attached to both ends. It was a cheaper alternative to factory ends.

 

O.