4.0 OHV how to tell which wire is for which o2 sensor

[thcscubajohn]

I recently installed my engine and I can't figure out which plug is for which o2. They bothe dangle down from the middle and could go to either side. One has a pink wire protector and the other black.

 

[Dirtman]

Plug one in and leave the other off. Whichever bank immediately throws a code is the bank where the unplugged wire goes.

 

[broncc]

bank 1 should use a gray wire and bank 2 should use a red wire

 

[thcscubajohn]

Plug one in and leave the other off. Whichever bank immediately throws a code is the bank where the unplugged wire goes.

I would, but its pre-obd and I somehow lost my diagnostic port when I swapped cabs

 

[RonD]

A shop reversed my O2 sensors, ran fine cold then bad after warm up
Ran fine at WOT(wide open throttle)
O2s are not used when engine is cold or at WOT

Set Lean on bank 1 and Rich on Bank 2 codes, lol

So won't hurt anything to get it wrong, just run poorly after warm up, if so swap them around

3 of the 4 wires will be the same on the truck side of O2 harnesses
In 1994 4.0l two will be different
Red/black stripe wire is drivers side(bank 2)
Grey/light blue strip wire is passengers side(bank 1)

 

[thcscubajohn]

Ok, I switched the wires and drove it. It seemed ro run fine warm before. I did get an intermittent check engine light that would clear itself if I kept driving or restarted the engine. There was no change to drivability with the code. Now there is no code, but it won't idle down. The rpm won't drop below 1.2-1.4k.

 

[thcscubajohn]

Ok so its a pain in the nuggets to fiddle with these wires. I managed to take pictures of the wires and they are plugged in correctly now.
Driver's side bank 2 has the red/black;


And the passenger side bank 1 has the grey/blue;

I'm glad I got the sensor with the longest wire for both sides, my hands could be alot more crispy.
Denso 234-4210

 

[thcscubajohn]

A shop reversed my O2 sensors, ran fine cold then bad after warm up
Ran fine at WOT(wide open throttle)
O2s are not used when engine is cold or at WOT

Set Lean on bank 1 and Rich on Bank 2 codes, lol

So won't hurt anything to get it wrong, just run poorly after warm up, if so swap them around

3 of the 4 wires will be the same on the truck side of O2 harnesses
In 1994 4.0l two will be different
Red/black stripe wire is drivers side(bank 2)
Grey/light blue strip wire is passengers side(bank 1)

Thank you Ron. You always have the right information.