Where is sensor 1 bank 2 95 2.3l Ranger and ?

[tbars]

...I know it might be a dumb question but seeing as I've only found 2, I would guess sensor 1 bank 1 is the upstream and sensor 1 bank 2 is the downstream sensor?

..I had a previous p1131 code which led me to a loose upstream sensor...Tightened and no problem since..

No codes problem?

..While at my buddies shop I asked him to scan my truck while running and just verify the o2 readings..S1B1 shows normal readings (say 700-900) but S1B2 is at zero and when the rpms are revved up I get 0-2 and back..

..I am surprised to not get a code but figured I would ask here as if the o2 sensor is weak I want to replace the correct one..

TIA..

 

[Bryan22]

4 cylinders don't have bank 2. only v motors will.

 

[Mac]

Never spent any time on a 2.3 until yesterday, about three hours looking at the Helms wiring diagrams. They do list/show bank i and bank 2. Only two wires from the CPU to the four injectors. One wire feeds #1 & #4 and the other feeds #2 #3. Do these motors fire twice per cycle like some of the later ones do? Really wondering.
Dave of the Nord

 

[tbars]

...Ran across some tech books and sure enough, S1B1 is the upper and S1B2 is the lower o2 sensor...The reason I had asked is, the scanners also read the 2 sensors as S1B1 and S1B2...

..Looks like I might just have to bite the bullet and replace both at the same time..

..Mac...The 2.3L 4 cylinders do have two coil packs and 8 plugs...1 coil pack and 4 plugs are the normal engine...The second coil pack and upper plugs are for a secondary burn which actually fire just before exhaust in each cylinder...