SR oxygen sensor problems

[srJOEYdet]

I have a 91 S13 with a 91 redtop from a 180SX. It has a bolt in the exhaust menifold currently, becuase I just sent my third oxygen sensor back to courtesy nissan. My first one I got from autozone, and my second one was from baxter auto parts. All three are the right size (the small one), but all three had the wrong plug, and did not read correctly. They had 4 pin square plugs, using 3 pins, and the plug on my harness is a 3 pin plug, oval casing.

The sensor from courtesy nissan was from a Z31 300SX turbo. I let the guy look up the part # for me, he said he was familiar with SRs. THe part number on the invoice and the box is: 22690-21P11

When plugged into my car it reads 200mv constantly. It goes down to 190 mv if you rev it hard. This is at a stand still, with the car warmed up (about 800ºF EGT). When the car is in motion, it reads lean all the time, and never changes on my autometer AF gauge. The gauge has 12v, and is hooked up proporly. I probably have at least 10 hours of experience soldering, and All my wiring is proporly soldered.

I am trying to firure this one out, so if anyone has any thoughts, please share.

Joey

[srJOEYdet]

BUMP

I know someone has found one somewhere. They can't be impossible to get a hold of.

[MeltedMonitor]

Joey,

Did you find a solution? I just installed my AF Gauge today and I am having the exact same symptoms. I get about 200mV constant, which changes a little bit, but not much. I have an S13 black top in my S13 convertible.

My understanding is that the three wires that come out of the o2 sensor are:
black: heater wire
black: heater wire
white: output wire

Theoretically the o2 sensor should work without the heaters plugged in, but the sensor must reach 600 degrees first. So I wired the output directly to the AF gauge and drove the car hard for a while. Acted exactly the same as having everything plugged in. Then I wired the heater wires to the battery and tried again, no change.

Darren

[SirWarrior]

according to a few sources
S13 SR20DET REDTOP o2 sensor = 22690-19P20 ('87 280ZX)

Hope that helps


Edit:
just noticed this thread is OLD

[MeltedMonitor]

The thread is old, but the problem is not! I brought this back up because it was relevant.

Well, I don't really know for sure if my information is screwy or if the o2 sensor is bad. I need confirmation either way.. anyone know about this?

[MeltedMonitor]

Anyone else hooked up an air/fuel ratio gauge in their SR20DET car? I need help with this!

[nismo2491]

check the voltage going to the a/f gauge too, if its not a full 12 volts at the gauge it will act weird.
KEvin

[MeltedMonitor]

Good thought, and I do have a full 12.8 V at the gauge... so that isn't it.

Regardless, I have had a voltmeter on the output wire from the o2 sensor and I have verified that the signal is what is screwy. Hmmm.. anyone?

[sr240mike]

Have you tried running the o2 sensor diagnostic at the ecu?

[90sr]

i am having the same problem, 90 240 with redtop sr, my a/f gauge is all hooked up properly lights up n everything, mine reads really rich tho, im not sure but i heard it might be cause of my cat, i had custom exhaust built 2 1/2 from downpipe back but i kept the old cat on there cuz im yet to get my high flow cat and i heard it might cuz the cat might be shit but i dont no.

chris

[MeltedMonitor]

Hmmm... the o2 sensor diagnostic?

The first thing I did was hooked the air/fuel gauge to the wire at the ECU and got the strange reading.

Secondly I verified that the wire I was connected to was the same as the one at the o2 sensor using the ohmmeter. Check.

Next I ran a wire directly to the o2 sensor to a voltmeter in the car. Same result.

What diagnostic are you refering to?

Darren

[MeltedMonitor]

Originally Posted by 90sr

i am having the same problem, 90 240 with redtop sr, my a/f gauge is all hooked up properly lights up n everything, mine reads really rich tho, im not sure but i heard it might be cause of my cat, i had custom exhaust built 2 1/2 from downpipe back but i kept the old cat on there cuz im yet to get my high flow cat and i heard it might cuz the cat might be shit but i dont no.

You say you are having the same problem, but that it is indicating a rich mixture. Is it changing at all when you drive the car? If it isn't then it does sound like the same problem... if it is changing then it would seem that the gauge is working and it isn't the same problem.

Darren

[90sr]

no it doesnt move at all, it just sits all the way rich, i dont understand it at all.

chris

[MeltedMonitor]

Well, I am on the lookout for another o2 sensor to try... I will let you know the results.

Darren

[mjjstang]

u should be looking for a wideband, cause u have an air fuel gauge and all.

[MeltedMonitor]

I was just going to throw another OEM sensor in there.... is that not a wideband? How would a wideband o2 sensor help me? Don't know much about these things.

[sr240mike]

A wideband would help you tune your car if you had an safc. Don't worry about it. Mjjstang just meant air/fuel ratio gauges aren't accurate at all, they're just a dancing light show.

[MeltedMonitor]

I do have an AFC and I plan on using my o2 sensor and gauge to do rough tuning before hitting the dyno. I dynoed it last weekend (without touching any of the default settings on the AFC) and I am running RICH throughout the pull. But without something to give me a reading I can't exactly adjust my fuel accurately.

The AF Gauge shows dancing lights, yes, but they correspond directly to the output voltage of the o2 sensor, right? If the o2 sensor is not hooked up to the ECU then I think the ECU runs in closed loop mode -- it shouldn't be trying to constantly adjust the fuel mixture based on the o2 readings. The o2 sensor is only "crazy" at idle I thought -- while the ECU was trying to optimize the fuel mixture. Under heavy throttle the gauge should process the information from the o2 sensor accurately, no?

What I want to know is how a wideband o2 sensor differs from a normal o2 sensor... so I went out on the net and found this:

Wideband is necessary when tuning a turbo car. Narrowband O2 sensors do not have enough range to differentiate a 12:1 AFR, from a 10:1 AFR accurately. They also don't have much range in the lean section. Normal O2 sensors generally can only tell rich from lean, and locate stoich for naturally aspirated cars.

So what is the output range for a wideband o2 sensor? Is it still 0-1V like a narrowband sensor? If it is then the Autometer AF gauge should work just fine with it, right? Remember, the gauge will just be for rough tuning then the fine tuning will be done on the dyno.

Darren

[MeltedMonitor]

More good information from dyezak at DSMTuners.com:

#1 What's wrong with the stock o2 sensor.

Before I say what is wrong with the stock o2 I'd like to define 2 words first so we can all be on the same page. Accuracy and Precision.

Accuracy is the ability for a measuring device to give a correct answer. Think of accuracy like this, if I'm shooting a gun at a target and hit the bullseye I'm accurate...I hit what I aimed for.

Precision is the ability to obtain repetable results. Think of precision like this, if I'm shooting a gun at a target and I hit 2" to the left of bullseye I'm not accurate (I didn't hit what I aimed for), but every time I shoot I hit 2" left of the bullseye...so I'm precise.

Now, what's wrong with the stock o2 sensor...It's HIGHLY inaccurate but moderately precise, and over time it looses it's precision. Also it is a narrow band o2 sensor, meaning tha it will only read an a/f ratio of about 14-15.1:1. Any richer than that and all it know's is "I'm rich, don't know how rich, but I'm rich" and any leaner than that and it thinks "I'm lean, how lean I don't know". It is meant to give fine adjustments to an ecu that is already in perfect tune. It's meant to compensate for small factors...clogged fuel filter, sticky injector, degrading compression etc. Start doing some wild #### and it alone can't compensate...this is why we have SAFC's and EMS's.

#2 Wideband differences

Wideband o2 sensors are designed and built to a higher standard, which accounts (minutely) for it's high price. They are VERY precise and pretty darn accurate. Now, what's cool is they are adjustable so you can make them more accurate (sort of like adjustable sites on your gun so you can move that shot 2" to the right to hit the bullseye). It uses a tunable resistor (pointiometer) to tune the o2 sensor to a VERY high degree of accuracy. Also (as the name implies) they see a very wide band of a/f ratio's (usually 8:1 - 20:1) so no matter where you are you know how rich/lean you are and can tune your car accordingly.