Bank 1 O2 sensor doesn't fluctuate - Any Ideas why?

[evilstuie]

Hi All,

I've finally got my project car running smoothly and reliably and I'm looking to get my fueling issues sorted and get a bit more economy out of the thing.

I need to trim some fuel, but before I do that I have some issues with the logging software I need to get sorted.

1. 1st and most important one is, no Bank1 O2 data
I have never been able to see both o2 sensor data streams. O2B1S1 always seems to sit at 450mV (+/- 10mV) where the 2nd bank sees fluctuations. I've tested, retested and retested again the wiring to confirm it is all correct to the sensors, swapped them with no change, and then replaced both of them, again with no change.
Is this a software issue, an OS issue, or something else?
I feel like the car is richening the mixture to compensate for no o2 reading on left bank and if I cut fuel to fix it it will lean out one bank even more or worse.


2. STFT & LTFT data not showing on graphs or charts.
This one may be due to LTFT not being enabled in the tune, but STFT should still show up yes?
This also raises another issue with the HPT scanner where the tables don't always populate. What is the difference between show zoom data only, on /off, and why can't I always select "Last" as the data to see?

I've put the tune file and the last log i took to see if anyone can help with this.

[2xLS1]

It is not a software issue. 450MV is the bias voltage the PCM supplies on the O2 signal terminal. When you unplug an O2 that is what a scanner will show. Since you have already tried another O2, unplug the non working O2 and short the O2 signal lead on the vehicle side of the plug to ground and see if the scanner shows the O2 signal change from 450mv to 0mv. If it doesn't the problem is in the wiring or pin connection between the PCM pin and wire terminal. To test the PCM you could swap the signal wires in the PCM connector between B1 and B2 sensors for testing purposes since you know the wiring is good on the other sensor. Both of these test procedures should help narrow down the problem.

[evilstuie]

It is not a software issue. 450MV is the bias voltage the PCM supplies on the O2 signal terminal. When you unplug an O2 that is what a scanner will show. Since you have already tried another O2, unplug the non working O2 and short the O2 signal lead on the vehicle side of the plug to ground and see if the scanner shows the O2 signal change from 450mv to 0mv. If it doesn't the problem is in the wiring or pin connection between the PCM pin and wire terminal. To test the PCM you could swap the signal wires in the PCM connector between B1 and B2 sensors for testing purposes since you know the wiring is good on the other sensor. Both of these test procedures should help narrow down the problem.

Thanks for that, I'll give it a try and see what I find.

[evilstuie]

It is not a software issue. 450MV is the bias voltage the PCM supplies on the O2 signal terminal. When you unplug an O2 that is what a scanner will show. Since you have already tried another O2, unplug the non working O2 and short the O2 signal lead on the vehicle side of the plug to ground and see if the scanner shows the O2 signal change from 450mv to 0mv. If it doesn't the problem is in the wiring or pin connection between the PCM pin and wire terminal. To test the PCM you could swap the signal wires in the PCM connector between B1 and B2 sensors for testing purposes since you know the wiring is good on the other sensor. Both of these test procedures should help narrow down the problem.

Just a quick question, which one is considered to be the signal wire on the 4 wire o2 sensors, signal low or signal high?
I'm using the below pinouts:

A = Low signal
B = High signal
C = Ground
D = 12v ignition

and PCM pintouts are(for left bank o2):
A = Blue 29
B = Blue 69
C = Blue 1
D = Blue 75

[2xLS1]

Signal high on O2. C and D are for O2 heater. Would need more information on the PCM type to help with PCM pins.

[DGS]

Here you go. High pins are 65, 66, 68 and 69. It's called out on the diagram. If you need more help, ask.