O2 Sensor Help

[teckersley]

Hi all. Yes, this is my first post but i have done a ton of reading, researching, and even ponied up and bought The Tuning School material so i can learn how to tune on my own. I am running into an issue and dont know where to look.

I have a 2006 GM 5.3 swap. I have it to where it idles pretty good but i was trying to do the VE and MAF tuning steps when i realized i am not getting any O2 % readings. it is showing voltage but not % on either LTFT or STFT. I have gone step by step though the VE and MAF tuning sections to get into the closed loop mode but I cannot figure out why i cannot see any % readings.

For what its worth, the standalone harness I bought came with the flat 4 prong O2 sensor plugs so i bought 2 brand new GM O2 sensors that had the same flat 4 prong connector. So the harness and O2 sensors area new. Hopefully this is somethings simple and stupid I have overlooked.

Thanks for any input.

VCM pics and tune attached.

VE and MAF TTS.hpt

[teckersley]

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[blindsquirrel]

Need to see a log file.

And you have a mess in your DTC settings, a whole shitload of codes for the upstream sensors have been turned off.

Bank 2 is the passenger side, not downstream/post-cat.

[teckersley]

Need to see a log file.

And you have a mess in your DTC settings, a whole shitload of codes for the upstream sensors have been turned off.

Bank 2 is the passenger side, not downstream/post-cat.

Thanks for that. I turned off those bank2 items thinking they were the downstream. Rookie move. Let me turn those back on and do a log file. It didnt matter when i turned them off but just to be thorough, i will enable them again and grab log file.

[teckersley]

Here is the tune with all O2 DTCs enabled and a log file afterwards. thanks for the help.

VE and MAF TTS.hpt

20211128 all O2 DTCs enabled.hpl

[teckersley]

Need to see a log file.

And you have a mess in your DTC settings, a whole shitload of codes for the upstream sensors have been turned off.

Bank 2 is the passenger side, not downstream/post-cat.

added new tune (ALL O2 sensor DTCs enabled ) and log file associated with it below. Thanks for the help.

[blindsquirrel]

Well that looks almost like the O2 signals are shorted to ground, and that's kinda unlikely so I'd suspect bad/junk sensors, or a mis-pinning problem on the PCM side of the O2 connectors.

This should be the correct diagram for your Delphi/case grounded (flat) sensors.

screenshot.28-11-2021 12.26.33.png

[blindsquirrel]

Hang on... is this a 2006 or 2001? Swap vehicle? The year of the engine is pretty much irrelevant as far as wiring diagrams go, the PCM and tune file and harness and sensors all have to be compatible, but you can plug in any year Gen 3 engine and the controls won't know the difference.

[blindsquirrel]

Don't turn on DTCs for O2 sensors that do not exist. There are no B1/2S2s anymore, and there never were any Sensor 3s.

[teckersley]

Hang on... is this a 2006 or 2001? Swap vehicle? The year of the engine is pretty much irrelevant as far as wiring diagrams go, the PCM and tune file and harness and sensors all have to be compatible, but you can plug in any year Gen 3 engine and the controls won't know the difference.

The motor is a 2006 5.3 with the 4L60E

[blindsquirrel]

Here is a baseline for the DTCs.
VE and MAF TTS- DTCs.hpt

Can I ask... what are you trying to do now, tuning-wise? Because you have Dynamic High RPM Disable set as if you wanted MAF-only (200rpm), and then MAF Fail High set as if you wanted VE only (14Hz). Very confused, and I bet the poor PCM is plenty confused too.

[teckersley]

Here is the tune with all O2 DTCs enabled and a log file afterwards. thanks for the help.

VE and MAF TTS.hpt20211128 all O2 DTCs enabled.hpl

[blindsquirrel]

Did the vehicle the PCM came from use flat case grounded O2s or square isolated ground O2s? Again (again), the year of the engine block and heads does. not. matter. for this part. You do not have a 2006 PCM and 2006 harness, as far as I am able to understand. The tune file says it's a 2001 Tahoe.

[teckersley]

Here is a baseline for the DTCs.
VE and MAF TTS- DTCs.hpt

Can I ask... what are you trying to do now, tuning-wise? Because you have Dynamic High RPM Disable set as if you wanted MAF-only (200rpm), and then MAF Fail High set as if you wanted VE only (14Hz). Very confused, and I bet the poor PCM is plenty confused too.

remember, i am literally a COMPLETE rookie. that being said, i was walking through the Tuning School manual trying to do the VE and MAF tuning steps. then, i realized this O2 sensor issue. the settings you are referring to were the steps outlined to do said table tuning. Long story short....who the hell knows

[teckersley]

Did the vehicle the PCM came from use flat case grounded O2s or square isolated ground O2s? Again (again), the year of the engine block and heads does. not. matter. for this part. You do not have a 2006 PCM and 2006 harness, as far as I am able to understand. The tune file says it's a 2001 Tahoe.

good questions, i didnt think it mattered BUT,

1)the ECM i bought separately along with the HP tuners suite from guy that was upgrading to the Holley system. We talked through all of the specs, and it seemed like it would work. Perhaps not?
2) The engine is a 2006 5.3 with the 4L60e from a Tahoe
3) yes, as recall, the original engine harness had the square O2 connectors. However when i bought the standalone harness it had the flat connector. The harness people said it "shouldn't" matters, so rather than cutting the connectors, i just bought 2 new genuine GM flat connector O2 sensors and used them. Maybe it does matter?

So what i have connected is: 2001 PCM, 2006 Motor, stand alone harness for gen 3 red/blue ECM, and flat connector (AFS75) O2 sensors for 2006 motor. I wonder if it is in fact a grouping issue since in 2003 GM switch all of them from case to isolated grounds???

thanks so much for your patience...obviously i and brand new to the game here.

[blindsquirrel]

You need to forget about anything to do with 2006, as all the sensors and diagrams and pinouts will need to be for the 2001 Tahoe since that's what the PCM is going to expect to be there.

[teckersley]

You need to forget about anything to do with 2006, as all the sensors and diagrams and pinouts will need to be for the 2001 Tahoe since that's what the PCM is going to expect to be there.

yeah, i noticed that the O2 part number for the 2001 tahoe is AFS138 whereas the part number i have installed is AFS75 which is for the 2006 tahoe. Based on what you see, do you think its literally that easy to resolve my just getting the AFS138 O2 sensors? I did some reading on this and the red/bllue harness matches the 2001 ECM so perhaps just switching sensors could do it?

[teckersley]

You need to forget about anything to do with 2006, as all the sensors and diagrams and pinouts will need to be for the 2001 Tahoe since that's what the PCM is going to expect to be there.

Hey Squirrel. do you mind taking a look at this log file I just did.

I replaced the AFS75 O2 sensors I had with some new AFS138s which are supposed to be for the 2001.

i dont really see where that solved anything. However, i found under engine, fuel where you can "command closed loop" and partially through the log file i clicked that. Then, I could see both LTFT and STFT under the SAE channels but still nothing under the AVG channels. they start low but then climb really high and the engine idles like a turd. Turn that off and she settles down.

Does this help point to anything else I can check? It at least seems like the O2 sensors are working but only under the "command closed loop".

Thoughts?

Thanks

20211129 command closed loop on.hpl

[blindsquirrel]

Where is the tune file that was in the PCM when that log was made? The most recent one you posted is the one where every single DTC for everything was turned on.

It runs like crap when you command CL because it's adding more and more fuel trying to get a response from the O2 sensor and it never changes so it doesn't know to do anything but add even more. O2s are still not working - 'working' means that they go above 450mv when rich and below 450mv when lean.

You have a harness or PCM problem, assuming the new sensors are actually good.

Fuel System Status is showing 'OL - Fault' but there are no DTCs set that should be there when that happens.

Unplug both sensors. Key on. In the scanner, do B1S1/B2S1 show something like 450mv?

Do you have good +12v at pin D (heater circuit) for both connectors?

Good ground at pin C for both connectors?

If I used the phrase 'use a test light as a jumper' would you know what that means?

[blindsquirrel]

If the engine runs fairly well when not forcing CL, there is no way those O2 readings of 50-70mv flatlined are accurate, it would run terrible if it were really that lean. Force CL and let it try to throw tons of fuel at it and the one sensor kinda-sorta picks up, the other one stays bottomed out and flat. Sure seems to me like something is pulling both signal lines down to near-ground. Really curious to see what they read with the sensors unplugged.