o2 sensor oddity, need help figuring this out

[atomicmecha]

Having an odd issue with my 92 GTR, at least I think its an odd issue because I only have my other obd1 cars to compare it too. I'm trying to solve a misfire and rich condition on the car and currently looking at the o2 sensors. I have a consult 1 cable and the nisscan software to monitor everything.

Here's whats odd, the "O2 Sensor" (which I'm assuming is the front one, or left sensor) shows a very slight movement, around 3-5 on the dial's 0-100 scale. Not sure what the 0-100 is, guessing 0v-1.00v given they are narrow band sensors?

First issue is that I feel like thats way too low for the sensor to be reading if thats the case?

The next issue is the "O2 Sensor RH" (which I'm guessing is the rear o2 and right side one) is just pegged at 100 all the time with no movement at all.

Makes me think bad sensor.

To check I unplugged the back/right sensor under the hood and the gauges never changed. RH one still showed 100 and the left one kept floating around 3-6.

Then I unplug the left/front sensor and both gauges go to zero.

I don't think thats how it is supposed to work but I'm still new to the Nisscan software and how the data should be read.

Can someone help shed some light on what is going on and if how this is reading is normal or do I have a major issue here?

 

 

This is what it shows with the car running at idle.

Edited August 2, 2023 by atomicmecha

[GTSBoy]

Obvs they should both, semi-independently, flick back and forth between about 0V and 1V, at least when the engine is running in closed loop mixture control.

It may not want to idle in closed loop, because at idle the sensors can be too cold to work properly. They become lazy and usually read very low. The ECU disregards them and just runs open loop.

They can also act like that if their internal heaters fail.

If they are old, it is a fair bet that either one or both heaters have failed or they are otherwise old and sick. they do not last forever.

It is also possible that the wiring is borked in some fashion.

[joshuaho96]

12 hours ago, atomicmecha said:

Having an odd issue with my 92 GTR, at least I think its an odd issue because I only have my other obd1 cars to compare it too. I'm trying to solve a misfire and rich condition on the car and currently looking at the o2 sensors. I have a consult 1 cable and the nisscan software to monitor everything.

Here's whats odd, the "O2 Sensor" (which I'm assuming is the front one, or left sensor) shows a very slight movement, around 3-5 on the dial's 0-100 scale. Not sure what the 0-100 is, guessing 0v-1.00v given they are narrow band sensors?

First issue is that I feel like thats way too low for the sensor to be reading if thats the case?

The next issue is the "O2 Sensor RH" (which I'm guessing is the rear o2 and right side one) is just pegged at 100 all the time with no movement at all.

Makes me think bad sensor.

To check I unplugged the back/right sensor under the hood and the gauges never changed. RH one still showed 100 and the left one kept floating around 3-6.

Then I unplug the left/front sensor and both gauges go to zero.

I don't think thats how it is supposed to work but I'm still new to the Nisscan software and how the data should be read.

Can someone help shed some light on what is going on and if how this is reading is normal or do I have a major issue here?

 

 

This is what it shows with the car running at idle.

Does it do that when you're cruising at say 60-70 kph? At idle it will bounce between 20 and 80 for some time before finally getting too cold to read and going down to roughly 0 and staying there even when the engine is fully warmed up. O2 will start sluggishly responding around 30C coolant temp when you're driving around as well.