Howdy folks,
Been awhile since I posted. But I'll give the jist of it, my brother has a 83 Toyota 2wd that we did a 22re swap, all components are from a 88. The guy we bought all the stuff from had it in his trail rig, so he cut out the non necessary wires, which is fine, we got just about everything that's needed all hooked up and the truck starts, runs, an drives.

But here's where we're at, the 88 is suppose to have a 4 wire o2 sensor, but we can only find 1 wire, it starts out at the ecu as a black wire, but then turns into a grey wire, is it suppose to turn back into black?

From what we read, we are suppose to have a black, a grey, pink with a green stripe and a white with red stripe.
We can't find the pink and green, White and red, or the black.

Can I convert from a 4 wire to a 1 wire?
Does anybody have a wiring diagram, pictures, suggestions, a Klondike bar, anything?
Thanks,
Azkid

 

I had azkid post for me because i couldnt remember my log in for the life of me, but ive got it figured out.

Anyways, I got a 4 wire universal o2 sensor that is

Black
Gray
White
White

in the truck I have traced

pin 12/18 (ox, Black wire covered in a gray shielded wire) all the way over to fuse panel

pin 10/18 (E2, Brown wire) over to fuse panel

Pin 8/18 (HT, Yellow w/white stripe) over to the fuse panel as well

So it should go

Sensor Black-Truck Black
Sensor Gray-Truck Brown
Sensor White- Truck Yellow w/White stripe
Sensor White-????

The last White wire on the sensor should be the ground for the heater correct, So can i just ground it to the truck or do I need to ground it back to the ecu just like the o2 signal grounds back to the ecu?

 

So if i understand this correctly, The HT pin on the ECU is like a floating ground that comes and goes as needed. So if i ground the Second white wire on the o2 sensor the o2 sensor would not actually heat up at all. So I need to hook up one of the White wires to the HT pin on the ecu and the other to a Switched 12v source correct?

 

So i was going thru the wiring, and found the 4th wire cut shorter than the rest, and it happened to be my switched power for the o2 sensor (Blk/yell stripe). Wired it:
Sensor Black-Truck Black
Sensor Gray-Truck Brown
Sensor White- Truck Yellow w/White stripe
Sensor White-Truck Black w/yellow stripe

and my CEL went out after pulling the neg bat terminal. I was curious if it would run w/o a CEL if i pulled the heating wires off so it was just a 2 wire and no go. Pulled the Truck Yellow w/white stripe wire off and the CEL was on instantly, plugged it back in and off it went. So 88 ECU with Heated o2 sensor cant be run as a 2 wire unless you fool it some how. I dont mind the 4 wire as i found the only 4 wire 4runner at my local boneyard yesterday so i scored the factory pigtails, the rest off the harness had been butcharded alreay but i was fortunate they left the body harness alone


Top half is plug by fuse panel, lower is plug to old o2 sensor.

 

I noticed that the side by the fuse panel goes, 4 wires than jumps to 5 at the pigtail, the other side is 5 wires back to 4 and stays 4 all the way to the o2 sensor.

SO, I unraveled toyotas sweet electrical tape to find:
That the 5th wire on both sides was actual connected to the shielding on the "GRAY" wire, which is just the black wire inside of it with shielding to prevent interference.



HOPE this helps anyone who has been having trouble with 4 wire o2 sensors, I scoured pirate, YT, Toyota nation, ect and couldn't find anything about my color 4 wire o2. The ECU pinout W/Heated o2 sensor is nice to have too!

 

You never gave the function to wire-color relation for the sensor. Atleast not directly, or I just missd it. So it is a little confusing maybe.

The 95 wiring book has these colors and functions.
Sensor #1, HT Pink-Green sensor pin#1, B White-red sensor pin#2, OX Black sensor pin#3, E1 Brown sensor pin#4, shielding is also brown.

The 88 has these.
Sensor #1, HT Green-yellow pin#1, B Black-yellow pin#2, OX Black pin#3, Ground Brown #4. shielding is also Brown.

Sounds like you got it working. GJ

 

THX MAN! Yeah, getting my cam timing spot on helped to haha, I was off one tooth.

Yeah looking at it i see what you mean, I didnt state the function of the wire colors on the o2 side. The o2 sensor im using is a universal 4 wire made by "pilot"

Black wire: o2 Signal Wire
Gray Wire: o2 ground wire
White wire: Heater +
White Wire: Heater -

hope that clears things up!