Wiring Connector problem?

[cmcfab]

Hello B2 Pros!
My step mom gave me her 88 B2 2.9L that’s been sitting years in my extra parking space.
A few years before she gave it to me, she had the engine rebuilt. But after noticing a sputter in the throttle I checked the engine and noticed that the guy who rebuilt the engine left the wire harness on the passenger side sitting almost directly on top of the header! So one of the harness connectors had melted and had exposed wires.
The connector was right next to the Oil fill cap, Passenger side. The connector has 5 wires into each side, but I just noticed that each side has different color wires! They aren’t the same colors for each connection point.

I ended up cutting out the damaged/burnt connector and wires. I went to the junkyard and clipped another connector off of a Ranger with 5 wires to splice into the B2 wires.
My problem is, it’s been years since I started the repair and now that I’ve got back to working on it I realized I must have thrown out the old harness. So now I don’t know which color wires on one side, connect to the other side!
Any insight would be greatly appreciated.
I hope my post makes sense.

 

[RonD]

Can you tell where either end of the harness goes to, that could narrow it down a bit

Book mark this page: https://www.therangerstation.com/tech_library/index.shtml

Scroll down to Electric diagrams, click on it

1983-1991 diagrams may help
Wire by color...........maybe, but quick to look thru

Thing is Ford did use the same color wires in different circuits

 

[cmcfab]

Ill take another look and see if I can get a better pic this afternoon.

 

[cmcfab]

So I pulled as much of the old hardened plastic harness sleeve going back. Looks like 4 of the wires goes back to a passenger side O2 sensor right in front of the trans.
Looking at a wiring diagram, I don’t see any connectors that change inline wire colors.
This is gonna be a tough one to figure out!

 

[RonD]

O2 sensors have their own wiring harness attached, 4 wires, can be any colors, it has a round connector that plugs into the vehicles harness

Looks like this: https://pg-cdn-a2.datacaciques.com/00/MTA0MTgy/18/10/16/979899502iu337l9/ba4cc49286f32f17.jpg

The different part numbers for O2s has to do with the length of the attached wires and connector style

Colors can be like these, depends on brand: https://i.pinimg.com/originals/0a/42/62/0a426277744731981e8389f87d9d5523.jpg

 

[piedrarock]

can I ask about number of o2 sensors for a 91 4.0l explorer engine ? The haynes manual seems to be indicating one , but i see lots of posts talking about two or more .
Also , Im gong to have to drill into to isert o2 sen. my exhaust system on my 4.0 swap in Ghia , and as i only have 16 inches of tubing after ex. manifold before it bolts to a muffler on each side , where would be best location for sensor (s)?

 

[RonD]

Yes, 1990-1992 4.0l only had the one O2 sensor after the Y pipe, 1993/4 had 2, 1995 and up had 3 or 4(dual exhaust)

If you have a dual exhaust then pick the easiest side and install an O2 bung

You can get weld in types like these: https://www.summitracing.com/search/part-type/weld-in-bungs-and-fittings/bung-type/oxygen-sensor

There is this type: https://www.summitracing.com/parts/wlk-41821

And a "no-weld" unit: https://www.3sx.com/images/thumbs/0006274_aem-no-weld-o2-sensor-mount-fits-175-200in-30-2355-200_320.jpeg

Upstream O2 sensors should be about 6 to 20 inches after exhaust manifold connection to pipe, so that part isn't that critical

 

[piedrarock]

Thanks again for your reply Ron , am I interpreting correctly with your response , firstly you saying only one sensor after the" y" pipe,
then 6 to 20 inches after manifold ends ( upstream)?, so that is total of two as it would be a pretty tight and aggresive "Y" to stay within 6 to 20 IN. joining both sides before heading downstream ?
Is it auto default that only one O2 sensor means one upstream and another down?
I look fwd to your replies . thanks

 

[piedrarock]

any takers ?