All the O2's show 1.27v until I start the engine at 57 seconds into the log. B1S2 seems to run at 0.745 most of the log. Except ... it seems to have some fits at initial startup, from 0 to about 280 seconds in then it levels out and doesn't move much. Are the down stream S2 sensors the self heated type? Perhaps the O2 sensor part of B1S2 is working but the heater part is not? B2S2 also has a similar startup pattern, though not as pronounced. They both seem to stabilize at about 285 seconds.

 

I think the only difference in the various O2 sensors is the length of the wire leads for the connector, and maybe the shape of the connector. Aside from that, exact same thing.

As they age, they do slow down. Heater circuits become less efficient, etc. May be a wiring issue. A dirty connection would also decrease efficiency of the heater circuit..... Can you post more of the log? (put it in spoiler tags please. )((do we even HAVE spoiler tags here??))



apparently so. But, if you edit the post after posting, they disappear.

 

The logs are here. The BlueDriver scanner saves the file as a delimited text CSV format file. I imported into spreadsheet program and made some charts from the data streams of interest. Click on this link. It takes you to the online accessible folder. Do what you will with them.

https://drive.google.com/drive/folde...lz?usp=sharing

 

A few more test drives with the truck, some more data logs captured, a repeat CEL and P0137 code kicked. Some more charts made and reviewed. Goto the link given above to view the data files and charts. To my inexperienced eye, the one O2 sensor is definitely acting differently. It has a much delayed startup, which makes me suspect the heater part of it. Also once it is up, it really doesn't move much off of midpoint. Ultimately, I can probably inspect and troubleshoot, root cause it to being heater circuit for the sensor either on the truck wiring or internal to the sensor itself.

Based on the logs, I have decided to go ahead and replace the downstream O2 sensor B1S2. I have just ordered the sensor B1S2 NGK/NTK 23132. When it shows up in a few days (Amazon) the truck will come in to the home garage to be checked over. I am planning to just replace the sensor. However at the time I crawl under the truck I will try to isolate the problem to either the old sensor or the truck side of the wire. Since the sensor is giving data and trending in the logs, I have already eliminated the truck side wiring as a possible cause.

To my inexperienced eye there is no obvious indication of a problem with the other upstream O2 sensor B1S1. However, it has been mentioned that O2 sensors get sluggish responding slower as they age and that the upstream sensor may reveal itself after the downstream is replaced. Since I now have some good logs to look at, as a matter of interest I have also decided to extend the experiment by replacing the O2 sensor B1S1 with NGK/NTK 23135. I will replace the faulty B1S2 first. Do some test drives with logs. Then I will replace B1S1 and drive again. In the end I hope to see three things:
- the effect of replacing the suspect faulty sensor B1S2
- the effect of replacing an old but apparently working sensor B1S1
- direct comparison of old vs new sensors Bank 2 vs Bank 1

Questions
- is everyone able to access and see the log files. Do they make sense to you? What other sensors / parameters should be compared together in a graph?
- If anyone with better depth perception sees anything different or anything else in the data streams please let me know.
- is anyone actually interested in this? Do I bother updating here any further or am I wasting my time doing so? I saw some initial "motherhood" statements about getting data and root cause diagnosis. I've done so, provided, and hear only crickets. (?). ... Except for HeyYou of course (you're awesome man )
...

 

I'm interested, but typically have a lot of priorities that out rank the forum - sorry if your response time expectations are not being met. Best to apply patience when asking for free help

Yep, you've done a good job at data collection, not so much on context though. Typically I need to connect what I've asked of the engine when looking at results. Maybe I could put together the story with rpm, vac, and tps - but I'd still be guessing. The charts could use some refinement as well, I keep having to zoom the legend to see the color coding - and I'd customize the xaxis so you're not reporting every rpm and can increase the font. I see a lot of tps cycle, is that you doing that with your foot or am I seeing dead spots in the signal?

I think consistently high negative LT fuel trim is somewhat concerning, however the dotted line that people tend to look just starts at 10% ... the computer supposedly won't kick a code until its double that. You perform WAY more maintenance than anyone I know, The only thing sensors I've cleaned are MAF, and the only emissions part I've cleaned is the business end of an egr valve. Neither by schedule; only when I can detect that I need to focus on them.

I thought it strange that you didn't mention any fuel injector maintenance. I tend to treat the injectors quarterly, and have found the Lucas brand to work pretty well.

Here is a short that discusses some of the possibilities for negative FTs. Have a look and see what you think.

If I have some time this week, I'll hook up my 04 2500 and see where my LTFT are.
I really like old school vac tests, they can tell you a lot about the general mechanical health of the engine. Gauge is cheap and easy to interpret...

https://www.onallcylinders.com/2016/...auge-readings/

 

you can rule out maf as speedy density fuel metering doesn't use them.
map is an important input for fuel trim for speed density systems. its important to look at data for both banks as a map reading with effect both banks. Its also important to look at what rpm the trim is out of "spec". check the freeze frame data.

what is it at idle and 2500 rpm? it will give you clues as to the source of the problem. cutting fuel only at idle on both banks ok at 2500rpm..check the map reading...possible manifold vacuum leak

 

I went for a quick errand, so I took the truck and I plugged in the elm interface and ran torque pro on my android phone after the engine got up to normal op temp (about 200F). I put a screen together for rpm, timing, vac, and graphed the left and right long term fuel trims. I'm getting BOTH positive and negative %s, and the waveform looked well under +-10%. TorquePro was circling and annotating some peaks intermittently, I'm not sure what logic they're using - and I didn't have my reading glasses on so I don't know what it was doing with those peaks. I've used my Actron scanner more than torque pro. Everything looked pretty much normal to me, performance is pretty good for a 3/4 ton 4x4.
This one is a 2004 2500 with 5.7, and it didn't ship with an EGR.
I bought the truck this year with about 160k miles, it had been in OH for the last 7 years and they don't have inspections. So there was some work to do so I could get a PA state mech/emissions inspection. I replaced all the o2 sensors because 3 out of 4 were setting codes, and they looked original. I also put in a new thermostat and waterpump because the old one was leaking. I replaced all 16 spark plugs with OE coppers, because I couldn't find when it was done last in the PO records. While I had the plastic off, I cleaned the throttle plate (didn't remove the throttle body). I ran two intervals with about 10 gals of gas and at least a double dose of lucas upper cyl lubricant (injector cleaner). It has about 165k on it now; its never set any codes since I did the maintenance. I have yet to really calculate mpg for this vehicle.

Maybe I can get some time this week to figure out how to get torque pro to datalog and dump it to my laptop. Let me know if you think that would help you out.

 

The only MAF I've cleaned is our 06 mustang... that cleaning really woke up the car with throttle performance, it had about 100k on it at the time and was original. Pretty sure engine management, in general, uses MAF for fuel decisions, not sure if Dodge even runs a MAF in these RAMs... I can't remember seeing that sensor.

The OP chart is showing rpm along the xaxis. I'm assuming its not sorted by rpm - and is just a representation over time, but the axis annotations are so small I couldn't easily read it w/o zooming in and out, and quickly got bored with trying to pull out context.

 

So I did a quick search on a process to datalog with torquepro.... and I found https://pidfusion.net/datalogs/. This site enables you to load up your datalogs (with a specific driving pattern) so you can compare your datalogs with other people's data logs. I'm not much into datalogs, I find the issue and check overall health with much less data... but if you wanted to compare the datalogs with others, you might want to check it out. Genearlly datalogs are good when you get stymied with basics and/or the problem is intermittent and isn't easily reproducible.

I'm not sure how much datalog comparison I could offer you given I wouldn't be replicating your engine exercise. Your analysis showed consistently negative and values beyond 10% LTFTs. I'm sure its not your secondary o2 sensor causing your newly discovered issue ; I think you should try to figure out why you have abnormal LTFT settings. Think it runs good now, take it back to the way it should be running and you'll likely be happier. I bought a hemi qc SLT 4x4 in 04 brand new and kept it over a decade and about 150k miles;the hemi 5.7s are really good performers when they are running as designed.

 

Thanks for the comments folks. Very much appreciated. Summarizing response to a few points made:
- there is no MAF on this truck. The only inlet sensors are MAP and IAT. Both are clean. Both have smooth acting data in the logs. Both appear to be working, though I have no resistance calibration charts to verify their accuracy.

- The X axis on the sample chart is time (T). There is throttle cycling as the data is captured over the course of a normal morning drive.
- to see the no load data, not driving, but at elevated rpms I have captured such sitting on the driveway. The file is called "Fast Idle .... "
- if it would be helpful to chart other variables ABC vs XYZ, I can certainly do that and push those to the link. The raw files are at the link where anyone can open them and manipulate them. Let me know what you would like to see. Available variables that have be captured and logged together on each run are:

• Time (second)
• Short Term Fuel Trim Bank 2 (%)
• O2 Bank 1 - Sensor 2 - Oxygen Sensor Voltage (V)
• Engine Coolant Temperature (°C)
• Absolute Throttle Position (%)
• Vehicle Speed (km/h)
• Long Term Fuel Trim Bank 2 (%)
• Intake Air Temperature (°C)
• O2 Bank 1 - Sensor 1 - Short Term Fuel Trim (%)
• O2 Bank 1 - Sensor 1 - Oxygen Sensor Voltage (V)
• Engine RPM (rpm)
• Intake Manifold Absolute Pressure (kPa)
• O2 Bank 2 - Sensor 1 Oxygen Sensor Voltage (V)
• O2 Bank 2 - Sensor 1 Short Term Fuel Trim (%)
• Long Term Fuel Trim Bank 1 (%)
• O2 Bank 2 - Sensor 2 Oxygen Sensor Voltage (V)
• Short Term Fuel Trim Bank 1 (%)

Consistently negative LTFT in the -6% to -15% range. Appears to be an indication of engine running a bit rich. Possible causes from video, thanks fj5gtx:
- Fuel Injectors. I have never removed them or done anything with them. Not had any cause to. None of the performance/drive-ability symptoms are present. I do put a bottle of liquid snake oil, aka fuel injector cleaner in the gas tank about twice a year. I have not really ever noticed any difference in operating performance before or after.
- Fuel pressure regulator. Where is it located and how do I check and test it. There is not a fuel pressure ID available on this obd scanner to see and log actual numbers. (I can google this)
- O2, S2 sensor(s) issue. From the catalog, there is clearly an issue with B1S2, which could explain B1 LTFT being -ve. However that does not explain B2 LTFT also always negative. Perhaps they are both shot?
- Oil was changed recently.