Wow! The strangest thing I see from this data is that there are no DTC codes. Given the data indicated, your check engine light should be on and multiple DTC codes flagged. What's most disturbing is that it appears as though all four of your O2 sensors are dead, which should have caused multiple DTC codes to trigger. The fuel trims are a reflection of whatever is causing the O2 sensors not to function. The start up base line fuel trim (LTFT) is at about -10% of normal operation and the real time fuel trim (STFT) is reducing normal fuel injector open time by another -9%. A -19% would be right at the edge of triggering another DTC code. Your car is shutting off like it is because it is being starved of fuel.

The upstream O2 sensors (S1 on both banks) should vary their voltage continuously between 0.1V and 0.9V. Yours are totally unresponsive at 0.00V. The 0.07V shown at one point on B2 S1 is essentially still dead.
These S1 O2 sensors control a great deal of how much fuel is released through your injectors. Without a voltage signal, there is no control and DTC codes should have been triggered.

The downstream O2 sensors (S2 on both banks) should fluctuate to some extent but hold fairly steady at anywhere between 0.2V and 0.8V, based on whatever is happening with the S1 upstream O2 sensor signals. These S2 O2 sensors do not effect the engine operations at all. They simply indicate whether or not your catalytic converters are doing what they are supposed to do. Your S2 sensors are also unresponsive at 0.00V, with the exception at one point where B1 S2 is shown at 0.31V. Once again, DTC codes should have been triggered.

No DTC codes for these apparently dead O2 sensors is very strange. I would say replace them all but I think something might be wrong with the O2 sensor wires and/or connectors. Check the condition of the sensor harness connectors. If there is input voltage being delivered to the sensors, there should be an output voltage signal unless the sensors are indeed dead as your scanner indicates. I know you just replaced these sensors. Something is killing them by a short circuit somewhere or the wire/harness connections are open.

I can't view those pics on the comp I'm using right now, but I don't recall seeing engine temperatures or loop status on them. Was that a warm or cold engine? If it was cold and running open loop, the HO2S readings won't mean anything because the sensors won't be at operating temperature.

Excellent point. The ECM ignores the O2 sensor signals at start up and until the engine is at operating temperature in closed loop status. If it never achieves closed loop status, that would explain why there are no DTC codes, since the ECM is ignoring the O2 sensors. The scan tool would still see the O2 sensor voltage signals, even though the ECM is ignoring them. The pics do not show engine temp or loop status.

I guess the oxygen may be the issues right now, I got the EVAP monitor settle today since I stop by to refuel. I just want to know if it may be a fuse that may be faulty or blown, if so where can I see it?

I guess to see the connectors, I have to disconnect the battery......again!

So I did the scanner again once I got home (12 mile drive back):

Fuel Sys 1 - CL
Fuel Sys 2 - CL
Calc load 29.4%
ECT 190 F
STFT B1: -9.4%
LTFT B1 :-10.2%
STFT B2: -8.6%
LTFT B2: -10.2%
MAP 9 (inHg)
Spark Adv 7.0 degrees
IAT: 106 F
TPS 0.0%
O2 B1S1: 0.000 V
STFT B1S1: -10.9%
O2S B1S2: 0.000 V
STFT B1S2: 99.2%
O2S B2S1: 0.570 (V)

It won't be a fuse because fuse #25 powers the heaters in all 4 sensors. With those negative fuel trims, I'm wondering if your fuel pressure regulator isn't blown. Pull the vacuum line off it and see if gas comes out, if so the regulator diaphragm is busted and the engine is sucking raw fuel into the vacuum line. That will cause a rich condition and make the ECM dial back the injectors to compensate, resulting in negative trims.

I just got back from the car, unplug the O2 and plugged them in, I guess we can say we are getting some vital signs that we want?

These are the following readings after letting the engine come to operation temp (I notice the engine getting warmer faster, must need an oil change). I suspect the downstream may not be accurate as the catalytic converters need replacements (last quotation I got was $1,200 for both lines, now it is more I suspect with all the theft here in California). I do plan to keep the car around until end of year the latest and replace it with a newer Pathfinder.

Calc Load 29.0%
ECT 185*F
STFT B1: 1.6%
LTFT B1: -10.2%
STFT B2: 1.6%
LTFT B2: -10.2%
MAP: 9 (inHg)
Spark Adv: 7.0*
IAT: 84*F
MAF: .72 (lb/min)

02S B1S1: 0.000 (v) -> it does goes up to 0.7 down to 0.000
STFT B1S1: -0.8%
02S B1S2: 0.000 (v) -> it does goes up to 0.07 down to 0.000
STFT B1S2: 99.2%
O2S B2B1: 0.570 (v) -> did trop to 0.000 then up again
STFT B2S1: 1.6%
O2S B2S2: 0.040(v) -> same as the other sensors
STFT B2S2: 99.2%

Those oscillations in the front O2's are normal, they're supposed to wobble between 0.6V or higher and 0.35V or lower. So that's healthy. The STFT's look healthy as well. If the LTFT's gradually drop off as you drive some more then I'd say it's fixed.

That's a huge improvement with the STFT for just unplugging and plugging back on the connectors. The harness connector contact pins may need a bit of cleaning with a shot of electrical contact cleaner spray to keep it right. The only other detail I would dial in is the ignition timing advance. At 7deg while idling, it's quite a bit off from the 13 to 17deg specification. Starting to look good though. Still, take a look at the fuel regulator vacuum line to see if it has fuel dripping from it, as VStar mentioned.

mdmellott wrote: ↑

Thu Jun 15, 2023 8:21 pm

That's a huge improvement with the STFT for just unplugging and plugging back on the connectors. The harness connector contact pins may need a bit of cleaning with a shot of electrical contact cleaner spray to keep it right. The only other detail I would dial in is the ignition timing advance. At 7deg while idling, it's quite a bit off from the 13 to 17deg specification. Starting to look good though. Still, take a look at the fuel regulator vacuum line to see if it has fuel dripping from it, as VStar mentioned.

I might need to get some of that spray, one thing I did notice is the fact that when I accelerate the car will not take off. It just revs without taking off as before. I did had it shut off on me/rough idle while I was backing up to park. Not sure if I should suspect a vacuumed leak, not sure how the timing got off as I have not touch the distributor cap. I wish I can do it but I might have a mechanic do it. The smell of raw fuel is gone from what I can tell. The EVAP monitor settled in after refueling the car, all I need now is the o2/EGR to settle to have them settled in.

If the engine revs normally but those RPM's aren't being translated into movement, that's a transmission problem and not the engine.

VStar650CL wrote: ↑

Sun Jun 18, 2023 6:37 am

If the engine revs normally but those RPM's aren't being translated into movement, that's a transmission problem and not the engine.

Sorry, it is more like the engine feels sluggish, wonder if it has to do with the spark adv been at 7 degrees vs been at 15 +/-2 normal range. I did refuel on Wednesday and notice 2 days later that it burned 1/4 tank already. How can I correct the Spark Adv to be at its normal range?

Too much advance will make the ECM dial back the power when it detects knock, so that could definitely limit your performance. You'll need a timing light to set it up perfectly, and the engine must be at the proper idle speed defined in the FSM. However, you can get it close just by turning the distributor and watching the realtime value on your scanner. If it's close to right and you still have power loss, then it's likely the problem is elsewhere.

VStar650CL wrote: ↑

Sun Jun 18, 2023 3:14 pm

Too much advance will make the ECM dial back the power when it detects knock, so that could definitely limit your performance. You'll need a timing light to set it up perfectly, and the engine must be at the proper idle speed defined in the FSM. However, you can get it close just by turning the distributor and watching the realtime value on your scanner. If it's close to right and you still have power loss, then it's likely the problem is elsewhere.

Thanks for the info, I think I am going to take it to a mechanic. I am tempted to see if I have a vacuum leak somewhere if that is the case, not sure how I went from 15 down to 7.

jetstream87 wrote: ↑

Sun Jun 18, 2023 8:07 pm

Thanks for the info, I think I am going to take it to a mechanic. I am tempted to see if I have a vacuum leak somewhere if that is the case, not sure how I went from 15 down to 7.

An old timing belt that has been stretched and worn old with age, will retard your timing.

mdmellott wrote: ↑

Fri Jun 23, 2023 11:27 pm

jetstream87 wrote: ↑

Sun Jun 18, 2023 8:07 pm

Thanks for the info, I think I am going to take it to a mechanic. I am tempted to see if I have a vacuum leak somewhere if that is the case, not sure how I went from 15 down to 7.

An old timing belt that has been stretched and worn old with age, will retard your timing.

Ugh!!!! So I have not gotten the chance to time the car properly - however the car decided to act up on the way home!

New ODB-2 DTC: P01500 - however I did a live data while driving.

Fuel Sys 2: OL-Fault
O2S B 2 S1 0.730 (V)
STFT B2S1 .0660(V)