Oxygen senor location/position questions (1 Viewer)

[Moby]

I'm going to be re-doing the O2 sensors in my customs exhaust so that I can move back to Toyota O2 sensors instead of the generic versions that I am currently using (thanks to Slee's O2 sensor bung for Toyota's O2 sensor design you no longer have to try to cut out the bung from your old exhaust pipes when building a new exhaust: Slee - Drivetrain - Drive Shafts).

Unfortunately my stock exhaust was long gone before I built my current exhaust so I don't have an original reference (I let a "professional" shop redo it some time ago and then replaced their bad design/execution myself). I want to make sure that I get the placement correct when I weld in the new bungs. My questions (couldn't find either of these in my FSM):

1. Which sensor goes to which bank of cylinders? I believe that the sensor for cylinders 1-3 goes to the sensor wiring that is near the front fender, clips to the frame, and then joins the main wiring harness under the brake booster. The exhaust for cylinders 4-6 goes to the sensor wiring that runs up above the transmission. Is this correct?
2. How are the stock sensors mounted in the pipes? By this I mean position - twelve o'clock (straight up), three o'clock...?

Thanks!

 

[Kynot62]

I cant tell you which one goes to which bank but they are located just in front of where your cat's used to be or just behind the drivers side mud flap and the other right next to the auto tranny. Both of mine are tilted at about 1 to 2 o'clock to the inboard side (I just looked). Unfortunately there was not room for two cats inside the frame so one of them was outboard under the driver.

I saw in one thread where somebody just put them both in the same pipe, I don't think the sensor really cares.

Hope this helps.

Tony

 

[Moby]

I cant tell you which one goes to which bank but they are located just in front of where your cat's used to be or just behind the drivers side mud flap and the other right next to the auto tranny. Both of mine are tilted at about 1 to 2 o'clock to the inboard side (I just looked). Unfortunately there was not room for two cats inside the frame so one of them was outboard under the driver.

I saw in one thread where somebody just put them both in the same pipe, I don't think the sensor really cares.

Hope this helps.

Tony

Thanks, this helps! The exhaust I built has both pipes inside the framerail into a single dual entry/dual exit cat. Works very well, except for a bit more heat under the transmission tunnel. One sensor per pipe prior to the cat, just like stock. I just want to switch back to Toyota sensors.

Anyone else on the wiring? I'm assuming the pipe inside the framerail is from the 4-6 cylinders (manifold closest to the firewall) and that the sensor in this pipe uses the sensor wiring that goes up around the transmission. If someone could confirm though that would be very helpful.

 

[Kynot62]

Joel

The original pipe for the 4-6 cylinders (closest to fire wall) is the one with the wire over the tranny.

I want to make the change you have, I hate that original pipe crossing under the frame to get back to the muffler.

Tony

 

[Bomar]

You can get the o2 flange here for $8.
http://www.toyotacatalog.net/M1WebG...UniqueID=2362E691-B816-4A15-8C37-27821BE183F0

 

[intense1]

I was thinking about making the same change! I was alos thinking about splicing the 2 leads together so that I only have to buy 1 O2 senser in the future, they're kinda expensive. Idk, it might be a bad idea.

 

[RockDoc]

You can get the o2 flange here for $8.
http://www.toyotacatalog.net/M1WebG...UniqueID=2362E691-B816-4A15-8C37-27821BE183F0

Good find

 

[Moby]

Joel

The original pipe for the 4-6 cylinders (closest to fire wall) is the one with the wire over the tranny.

I want to make the change you have, I hate that original pipe crossing under the frame to get back to the muffler.

Tony

Excellent, I've got them right then. Thanks again!

There is plenty of room for both pipes inside of the framerail. Well, maybe not plenty but it is doable Here is my original exahust build thread: https://forum.ih8mud.com/60-series-wagons/231789-new-exhaust-work.html

Couple of things that I'd change about this design:

1. The location of the flex joints make it a little tricky to get to the manifold flange bolts. Not a big deal but I'd lower them some if I did it again.
2. There is more heat inside of the framerail and thus up the transmission tunnel. I'm going to be adding more external heat sheilding to complement the stock heat sheilds. I'm also going to consider adding heat sheilds to the O2 sensors.
3. I'd put a joint between the cat and the downpipes. As it is it is a real pain to work this up past the axle and into position.