ECU O2 sensor wiring HELP P0134 stuck in open loop

[JamesMSP2003.5]

Hey Everyone,

I am having a huge problem with my o2 circuitry.
I get the P0134 no activity from the upstream o2 sensor; I changed the sensor with a new OEM denso unit and I am still not getting any o2 voltages on the when I data log from the obdII port. i read 0.00V on the front o2 and 0.005 volts on the rear.

The previous owner had done some work on the car but it was all quality work for the most part.

I have looked at the ecu wiring and found that pin 60 and pin 35 the front and rear incoming o2 signals respectively have been spliced together and connected to a black and white wire coming from the firewall stock wiring harness. There are also 2 grey wires that seem to be for continuing the path of the o2 wiring.

Does the pink/blue pin 60 and blue/yellow pin 35 change into a larger grey wire as it travels through the wiring harness??

I have drawn a picture to help describe what i am seeing.

This problem is preventing my car from going into closed LOOP operations. and my fuel trims are always 0% !!! I don't think my car has ever been in closed loop before. poor car

View attachment o2 wiring.bmp

 

[JamesMSP2003.5]

UPDATE:

I cut off the black wire so that it nolonger shorted pin 60 and 35 and is now connected to nothing.

MY car now finally goes into CLOSED LOOP i am reading primary voltage and also getting fuel trim calculations. But now I am running crappy because ssafc was tuned well in vaccuum when in forced open loop. I had values of 9.6 ish in all vaccuum. Now my fuel trim says +8% I will set all vaccuum settings back to 10 and hope for the best

what on earth was the previos owner trying to acomplish by doing this???
My only guess is that my rear o2 is NOT there because he put my wide band there and was trying to simulate the rear o2 sensor by sharing the primary signal with the rear o2 signal input to the ECU.

But this still does not explain the reason behind the black wire shorting my o2 signals out?? perhaps on purpose????? and where should this wire go? It looks like stock factory wiring. and is more than likely a ground to somthing.

 

[jumaaneface]

Anyone shed some light on this? I experienced the same thing...Quite confusing to say the least.

 

[jitters]

My cars wiring was also spliced just like this. I believe all MSP are like this. I never had a problem with my car but posted a question when installing my SSAFC. http://www.mazdas247.com/forum/show...ase-chime-in&p=5713322&highlight=#post5713322

I was concerned when installing my SSAFC and wanted to see if anyone else had the same splice. My thread probably doesn't help but I left mine the way it was and installed my SSAFC and never had any problems.

 

[jumaaneface]

Mine ended up having problems because of it. It honestly didn't look factory at all. Removing that splice stopped my cel for my primary o2 sensor