• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Testing Jeep O2, Oxygen sensors

I ran the engine today
I have a new 02 sensor and it still runs the same as with the bad o2.
Although the heater is on all the time the o2 voltage should be switching low to high.
The voltage slowly decreases as it worms up but never gets below 4v or so.
It doesn't go rich/lean either. Stays on lean all the time but runs very rich.
This is all at idle.
Before I started this thread the engine would try to quit at stop lights.
Not sure if that's due to a bad cat. The temperature difference between the front and back of the cat is only about 75 degrees. Hotter in the rear of that cat.

I still have to correct the o2 heater from staying on but I shouldn't be getting the above issues.

Any thoughts?
Thnaks.
 
Although the heater is on all the time the o2 voltage should be switching low to high.
The voltage slowly decreases as it worms up but never gets below 4v or so.
It doesn't go rich/lean either. Stays on lean all the time but runs very rich.
This is all at idle.

Ok, so when the sensor is cold it will read 5v, which is lean.

As the sensor warms up it should start reading accurately, which will almost always be rich. The computer is waiting for the voltage to drop to about 1v so it can attempt closed loop. Rich/lean only updates when in closed loop.

If your sensor never sees a rich condition then there could be an exhaust leak, any cracks in the manifold?
 
If your sensor never sees a rich condition then there could be an exhaust leak, any cracks in the manifold?

Nothing that I can hear. I've heard exhaust leaks before in other vehicles but not this one. That doesn't meant that there isn't a small one.

Also got some new data I found today.

Tested power at fuel pump connector. Key off got no power. Key on got power. With the jumper wire out from between pins 85 on the FP and o2, there was no power to the fuel pump connector with either key on or off.

Checked power to O2 with key off, key on and start. Like before, I had 12v with key off, and it dropped to 0v with the key on while the fuel pump was priming. Once the fuel pump stopped priming after 2-3 seconds, the voltage went back to 12v. Started the engine and the O2 voltage dropped to 0v again. Something new engine running o2 gets no power.

The way I see it, there is something wrong with the F22 14OR circuit because pin 87 on the fuel pump relay should not have any power with the key off.

Suspecting there is a short in the F22 14OR circuit causing pin 87 to be hot. This in turn is causing the O2 to pull voltage from the battery.

Also, with the fuel pump relay and O2 relay sharing the ECU ground, the computer cuts ground to the O2 relay for the heater to turn on, but the relay is still energized from the fuel pump relay ground.

Likely, the O2 heater will never work until the o2/FP jumper wire mystery is solved.

Any idea as to a work around for that?
 
Ok, so when the sensor is cold it will read 5v, which is lean.

As the sensor warms up it should start reading accurately, which will almost always be rich. The computer is waiting for the voltage to drop to about 1v so it can attempt closed loop. Rich/lean only updates when in closed loop.

If your sensor never sees a rich condition then there could be an exhaust leak, any cracks in the manifold?

I found an Orange wire with black strip which is a power wire to the o2 senasor relay had been cut and soldered to a red hot lead leaving the rest of the OR/Bl to the fuel pump resistor dead.

I would post a picture of the wire switch but there is no way to do so without that picture coming from a URL.

I reconnected the wires back and this is the results.

https://youtu.be/GKnDxs-Xxrc

Doesn't go open/closed thoug and don't know why. Also not sure if STFT is normal.
 
I found an Orange wire with black strip which is a power wire to the o2 senasor relay had been cut and soldered to a red hot lead leaving the rest of the OR/Bl to the fuel pump resistor dead.

I would post a picture of the wire switch but there is no way to do so without that picture coming from a URL.

I reconnected the wires back and this is the results.

https://youtu.be/GKnDxs-Xxrc

Doesn't go open/closed thoug and don't know why. Also not sure if STFT is normal.

Ahah, so there was more meddling with that o2 power wire. Nice find.

Watched the video and everything looks perfect! No complaints.

As for some terminology, you don't want open loop because that is the unmetered mode. Closed loop is when it uses the o2 sensor to run just right, and should be the goal to hit.

You're in closed loop, the o2 sensor is swinging enough for a rich/lean change, and your STFT is actually fairly good, I'd call that a success.

:party:
 
Question for the Renix guys:

Two years ago I bought one of Nick's excellent REM units prior to a California smog check, and determined I was stuck in open loop. I was running a NTK 23553 o2 sensor at the time, and I ordered a new one and installed to find the same result. As a test, I swapped it out for an old Walker 250-23501 that I had as a spare. The Walker immediately fixed the issue and dropped the ECU into closed loop.

Both NTKs were metallic three-wire sensors as seen here:

9vO6FSk.jpg


The Walker was a ceramic three-wire like this:
pf5KWB7.jpg


I passed smog with excellent numbers, and have been running the Walker since. According to the REM, I have consistently gone into closed loop within ~30 seconds of starting the Jeep every single time. The o2 voltage fluctuates consistently from low-high as well. I kind of wrote this off to the older ceramic Walker being more appropriate than the newer, metal NTK.

It's two years later now and time for another smog check. I typically do a pre-emptive tuneup and I was planning on popping in a new o2 to alleviate anxiety. I went to order another Walker but the product images on their catalogue http://www.walkerproducts.com/wp-content/uploads/2018/11/CATWC37-18%20US%20OE%20(250-)%20Oxygen%20Sensor%20Catalog.pdf now show the 250-23501 as being the same metallic construction as the NTKs that weren't working:

AUntqFP.jpg


This same product image is reflected on RockAuto as well, but I will note that the RockAuto image for the NTK still shows a ceramic o2 sensor when I know that one is also metallic. Both RockAuto, Amazon and a couple other parts places I checked showed the Bosch 12009 as ceramic in the pictures, so I ordered one from Amazon... surprise surprise, it arrived and is also metallic. The part page for that sensor on their own website shows it as ceramic ( https://www.boschautoparts.com/en/auto/oxygen-sensors/premium-oxygen-sensors?partId=12009 )

So now I'm thoroughly confused - I know that product photos with generic things like o2 sensors can't really be trusted to be accurate but this is annoying. Do Renix systems prefer the ceramic heated sensors? Did I get two bad metallic NTKs in a row? Are you guys running metallic sensors and successfully getting into closed loop/passing dyno-based smog?
 
I passed smog with excellent numbers, and have been running the Walker since.

It's two years later now and time for another smog check.

The real question is, does your current sensor still work properly? They should last you a fairly long time if you aren't running rich or swamping it constantly.

Hard to know for sure about sensors matching their picture unless you order it or call me thinks.
 
The real question is, does your current sensor still work properly? They should last you a fairly long time if you aren't running rich or swamping it constantly.

Hard to know for sure about sensors matching their picture unless you order it or call me thinks.

Yeah the current ceramic Walker is working properly - all the readings on your REM are correct and my mileage is good/as expected with my modifications. At this point I'm planning on doing my smog check as-is since everything is untouched since my last Pass. That's all fine and good.

I guess my question is really a larger one as to whether or not the newer non-ceramic O2 sensors are correct fits for the Renix system.
 
I guess my question is really a larger one as to whether or not the newer non-ceramic O2 sensors are correct fits for the Renix system.

Good Question. I was worried about my first solid NGK since it was so different looking from the old ceramic one, but it has worked just fine for me for the past couple years. Odd it wouldn't quite work for your setup.
 
Good Question. I was worried about my first solid NGK since it was so different looking from the old ceramic one, but it has worked just fine for me for the past couple years. Odd it wouldn't quite work for your setup.

I was especially confused since I tried two brand-new NTK/NGK and neither of them would go closed-loop two years ago when I tried them. 1988 4.0/AW4 for the record, and I've done every single Cruiser54 tip on the dang thing.

I'll throw in this metallic/solid Bosch 12009 I just got, and see if it goes closed.
 
Those NGK/NTK let me down twice from Rockauto. Ended up getting the Bosch ceramic one. My mt2500 was the source for my data on the NTK not switching properly.

I was getting ready for a CA smog test and checking my trims with the scanner and glad I had the scanner cuz the rig actually runs good albeit rich with the faulty 02 sensors.

My 89 now has 556,000 miles on original engine and transmission and 100 mile round trip a day for work. Love it still since I bought it new in 89.
 
The real question is, does your current sensor still work properly? They should last you a fairly long time if you aren't running rich or swamping it constantly.

Hard to know for sure about sensors matching their picture unless you order it or call me thinks.

Zinc and phosphate in older oil formulas (oil burners) and silicates from old conventional coolant spills on the O2 sensor white area, or exhaust leaks with coolant in the exhaust contaminate and kill the active catalyst in the sensors quickly. Normally they are good for 100,000 miles on the old Renix rigs. barring any hit and run road hazzards like a driveshaft road kill attack or exhaust manifold attack, LOL.

But his question has me wondering if the old style Real Renix sensor is vanishing and the computers are replacing them with the HO sensors by mistake. If that is the case we need stock up before the the good ones are all gone, and get in touch Bosch/NGK management and let them know. The Off road outfirts like 4WD online might have some clues as to what is going on.

I would take a torch and heat the metallic ones up on a bench vise using the old unmounted test methods listed on line from 10-20 years ago, and see if the metalic ones generate a 0-1 single, or if they show a resistor path that confirms it is an HO or Renix O2 sensor. I have been wondering for 2 years now, reading these recent NGK metallic Renix sensor's not working posts, if the retailers are selling HO O2 sensors for Renix, not knowing they are not the same?????
 
Good Question. I was worried about my first solid NGK since it was so different looking from the old ceramic one, but it has worked just fine for me for the past couple years. Odd it wouldn't quite work for your setup.

That is good to know!!!! That is the first time I have seen a post saying that, other Cruizer54's posts years back saying the NGK at that time was better, and not knowing if the NGK's he had used were white ceramic or silver-metallic.
 
:eek::eek::eek:

My 89 now has 556,000 miles on original engine and transmission and 100 mile round trip a day for work. Love it still since I bought it new in 89.

:clap::clap::clap:


:woohoo:

:worship:

Impressive, Most Impressive, Mine is sneaking up on the 300,000 mile number.
 
But his question has me wondering if the old style Real Renix sensor is vanishing and the computers are replacing them with the HO sensors by mistake. If that is the case we need stock up before the the good ones are all gone, and get in touch Bosch/NGK management and let them know. The Off road outfirts like 4WD online might have some clues as to what is going on.

This was the sneaking suspicion I had, thank you for putting it into words. It just seems odd that suddenly it's very difficult to get the ceramic sensors - whether or not that's by updated/cheaper designs or database/AI error is the question. The Walker catalogue I linked above shows what appears to be the correct ceramic model as 250-23500 but for a Jeep 86-90 4cyl so I imagine it's somewhat different.

It's encouraging that Nick's NTK is working; if anyone would know his O2 was out of spec it'd be him :laugh:
 
If not then all of Nick's followers are in serious trouble, LOLOL.

Nick told me recently, and I think I recall confirming, the Renix Era 4 bangers were throttle body injected, with the newer style 0-1 volt, voltage producing GM style O2 sensors. I forget if and when they went to multi port injection on the 4 bangers, but I thought the 87, 4 bangers were multi port years ago, now I am not sure. Isn't Nick working on REMs for the four bangers??? Did they get used on GM XJ 4 bangers with throttle body injection back in 87? or later? IIRC the 1995 Blazer still had throttle body injectors from GM. Then they went to a bastard spider injector design, buried under the intake manifolds.

I do know the 4 banger XJs always had the GM 0-1 volt style O2 sensors, and they would not work on ours. Renix O2 did not produce a voltage, it is a variable resistor O2 sensor with the ECU supplying a 5 volt feed to it.

Unless of course my memory is off on what I read, or others had it wrong?


This was the sneaking suspicion I had, thank you for putting it into words. It just seems odd that suddenly it's very difficult to get the ceramic sensors - whether or not that's by updated/cheaper designs or database/AI error is the question. The Walker catalogue I linked above shows what appears to be the correct ceramic model as 250-23500 but for a Jeep 86-90 4cyl so I imagine it's somewhat different.

It's encouraging that Nick's NTK is working; if anyone would know his O2 was out of spec it'd be him :laugh:
 
I put in the metallic Bosch 12009 this evening. First off I compared them and noted that it had a much smaller threaded portion than the ceramic Walker (by nearly half) - however when you line up the shoulders/crush washers the small sniffer ports in the heads are in the same location relative to the exhaust stream. It's been two years so I can't really say for certain, but the Bosch metal body seemed to be a slightly larger diameter than I remember the NTK being. It was oddly difficult to get it threaded into the downpipe for some reason, the damn thing refused to pick up the thread. Once I got it in and started the engine, it dropped into closed loop in park/at idle around ~20seconds the first time. I watched it for a few minutes and noted it went into decel loop a couple of times very briefly while it hunted the RPMs a bit. I imagine that's fairly standard for a brand new O2 heating up the first time.

Took it for a short ~4 mile drive with a engine-off stop halfway, under standard driving conditions up to 60mph and never saw it go into open loop. Dropped into closed almost immediately after the hot start. The REM shows it fluctuating voltage across the range as it should, but the update times look sliiightly slower between voltage intervals than the Walker. Overall it looks to be working great.

The halfway point in the drive was a 7/11 where I bought a $5 lotto scratcher that just returned $400, so now my superstitious pre-smog luck variables are off the charts in all directions... at this point I'll either pass cleaner than a Prius or get t-boned by a pre-recall VW diesel as I pull into the station :laugh2:

My 89 now has 556,000 miles on original engine and transmission and 100 mile round trip a day for work. Love it still since I bought it new in 89.

That's excellent man, you gotta love these old things. I'm only at 203,000.
 
Back
Top