Where to mount my wideband O2 sensor on my 2000 XJ?

[bajabronco]

I just got my wideband o2 sensor in the mail today, and I am looking for a good place to mount the o2 sensor on my 2000 XJ with the dual pre-cats after the manifold. I am going to be swapping the stock exhaust manifold for a banks header, but there still doesn't look like a good place to mount the o2 sensor before the dual cats. I just wanted to see where other people ended up mounting their widebands when they have dual pre-cats. I was looking at possibly the area right after the manifold flange mount on the y pipe/cat side, but it looks really tight.

 

[RCP Phx]

Are you actually planning a permanent gauge? Your in a little bit of a catch-22, you either have to monitor all the cylinders after the pre-cats or monitor 1 bank ahead of the cats. I have seen 2 wide-bands used.

 

[bajabronco]

Ron, I bought the AEM gauge and sensor to mount it permanently in the XJ. I was under the impression that I had to mount the wideband before any cat to get an accurate reading.

 

[bajabronco]

In looking at the exhaust system, I was thinking the only location to mount it is where the large red circle is, where the y pipe merges. I considered mounting it in the flange right after the manifold - small red circle, and before one of the Cat's but I am not sure there is enough room there.

 

[RCP Phx]

Like I said, kind of a catch 22 !

 

[Ralph77]

So I had to google wide band O2 sensor.
Shows how little I know. LOL.

Assuming you are going to run this one:

https://www.bankspower.com/i-788-ex....0L GAS||model=CHEROKEE||make=JEEP||year=2000

What are you running for a pipe off the Banks Header?
Are you doing a custom exhaust?

In a Walker Exhaust for an '00 made after 1/20/00 you would run a Y pipe, no cats, for a Federal Emissions or the dual cat in the picture you posted for a CA Emissions.

The intermidiate pipe attached to that has a bung hole that has a bolt in it but where the downstream O2 sensor would be on a Federal Emissions vehicle.

https://www.napaonline.com/en/p/EXP53440?searchCategory=c6.s1&searchIndex=Universal

Enlarge the picture and look closely at the right side of the pipe.

 

[Ralph77]

I'm sorry it is not the downstream O2 sensor that would be there but the upstream on a Federal Emissions vehicle.
I got confused. LOL.

 

[bajabronco]

My XJ looks like the pic above, two O2 sensors in the exhaust manifold and two immediately after the cats, thats it, a total of 4. No other o2's farther downstream

 

[Ralph77]

My XJ looks like the pic above, two O2 sensors in the exhaust manifold and two immediately after the cats, thats it, a total of 4. No other o2's farther downstream

But do you have that intermediary pipe after the dual cat like in the Napa link?
And if so is there a bung hole there?

 

[bajabronco]

No o2 bung hole there in the intermediary pipe on my truck right now, that pipe basically runs from near the oil pan drain plug past the Tcase to the third cat. I have no problem welding in a new o2 bung, but I was trying to figure out the best place to locate the wideband o2 for the most accurate reading, and to see where others have mounted it. I want to be able to get accurate data logs for when I tune my stroker. I guess with the space available I'll have to put it where the red circle is downstream.

 

[Ralph77]

To bad.

I just replaced the whole exhaust, on my '00 with CA Emissions, new dual cats back and that Walker intermediate, sorry meant to type that not intermediary, pipe has the bung whole for an O2 sensor plugged with at bolt already in it.

Thinking it is only about 2 inches back from where you drew that circle and if you had it would save you some time.

 

[cwyman6]

Just hollow out the precats and mount it where large circle is. Move down stream o2s to after 3rd cat and extend the wires. Smog would even know

 

[chasdb]

I agree its best to monitor both banks before the cats, I'm no expert. I have a 2000 federal emissions and am running the earlier style Banks manifold and have installed the wide band's O2 90 degrees from the factory's upstream O2 sensor at the collector (your large circle). I don't have precats since it a federal, and Banks EO number is the same for Torque Tubes and Revolver header so smog guys haven't caught that. I like being able to see it for peace of mind especially when towing when failure could mean a derailed vacation.

I had a JBA and wrapped it and it failed in less than 2 years in So Cal. The Banks I got ceramic coated (Jet Hot) and that lasted a few climbs to Big Bear and Round trip to Moab before it started flaking off.

Looking at the sidewinder header, there isn't much room at the outlets with the Ca upstream sensors already there. So I think you are right at installing them above the precats if you want to constantly monitor your AFR. I think I have a set of precats if you want to experiment on them. Maybe install on both banks and you can toggle between them. I think hollowing out cats may log a cat in-efficiency code. I also have a 2000 federal y pipe you could borrow for motor tuning so you can read both banks without precats.

If I recall correctly, when Robert ran the KOH EMC '12 he lost his motor on the lake bed. Had a Pace Setter dual outlet header and had the wide band on the rear bank. Front bank went lean

 

[lazyxj]

My 2001 XJ has the twin mini-cats and when the stroker was installed, a pair of bungs were welded in for the wideband sensors, to work with the AEM gauge
Having only one gauge, i have to manually switch from one sensor to the other.
I have a small fortune in O2 sensors invested.

 

[bajabronco]

LazyXJ -I have the same headers as well. I was reading on the HP Tuner site that people with an o2 sensor after the cat only experience a deviation is only +-.2 - https://forum.hptuners.com/showthread.php?13481-OK-so-whats-the-deal-with-WB-s-after-cats

but I am still thinking of going before the cat. Have you found a big deviation in the readings between the front and rear banks on your two wide bands?

 

[lazyxj]

LazyXJ -I have the same headers as well.

I am still thinking of going before the cat. Have you found a big deviation in the readings between the front and rear banks on your two wide bands?

The wide-band O2 sensors must go before the catalytic converters to get an accurate reading of the mixture.
I notice no major differences in mixture readings when switching from one sensor to the other.
Fuel trim levels can be read with OBDII monitor, such as a ScanGauge or Ultragauge.