STFT oppposite of each other at times. O2s reading different of each other

[Takid455]

STFT are oppposite of each other and seem to be doing a criss cross pattern. At times Bank 2 STFT flat lines at -13.3%. O2 readings don't seem to following each otherr either.

One would think there is an air leak somewhere.
Being cruise is the bulk of time logged which is in the 18-2200 rpm range, this is where I am noticing the behavior. Obiously , they go out of play in closed loop operation.

Thing tested:
Switch O2 sensor pins on ECU . made things worse
New Denso O2 sensors (4th gen Camaro in place of the Bosch 13444) units - no notable difference
WB readings are within 0.5 of each other on each bank

Performance is smooth, WB readings are seemingly accpetable. Still dialing things in however.

Havent checked sensor side vs ecu harness side of the connectors yets to confirm wires are not crossed.

Is this something others have expireneced? If so, what resolved it? Trying to search for ideas where/ what to tune/ address, ect.

A short scan is atached. Most scans logged have similar patterns in respect to the question.

[5FDP]

I've had open loop STFT disabled if I was using open loop with a wideband so maybe the first time I've kinda noticed that. I tend to ignore anything o2 sensor/trim related with open loop.

[Takid455]

Unless I'm missing something, I think it is set to closed loop. LTFT are not enable as I am tring to focus on the STFTs. That make sense?

[5FDP]

I can't see your tune but that log stayed in open loop the entire time.

[Takid455]

You're correct. Never set the ECT vs IAT temp to enable CL. Had it at 284. my bad

Aside question, wouldn't the O2 & trim readings act/ record the same in open vs close just not have nay affect?

[Takid455]

STFT being almost identically opposite? Using 0411 ecu. In open loop, performance is smooth and strong. Haven't checked for vacuum leaks but I am ruling them out for now. Its a traditional intake & 4150 flange accumfab thottle body setup. Wiring appears to check out in ECU pins (26, 66, 29 & 69) and at O2 sensor connectors. Running 4th gen LS L & R sensors. Denso 234-4025 & 4087. Long tube headers with sensors in collectors a couple inched before V band flange. No exhaust leaks up or downstream. It is an X pipe system. X pipe is 2- 3 ft from header flange. At a loss to where to look & check as things seemingly check out. Most likely it will be a simple stupid fix, just need to find it. I have LTFT turned off for the time.

[SlowNStock]

There's nothing inherently wrong with small, opposite STFTs (say +/-2%), especially over a short time - both banks aren't identical and O2 switching isn't forced to match between banks.

Large, opposite fuel trims are a concern, though. Things that jump out from your logs are that (1) STFTs are unstable - they quickly swing to an extreme at steady state, (2) which extreme they flip to isn't consistent - in the first log, both banks range from >20% to <-10%, and (3), Bank 2 seems to go a little lazy from time to time (no switching) - take a look at 04:33.374 - 04:43.418 in your first log, B2 sits static, which drives STFT to go max negative (it does this several times in this log).

Have you double checked that the sensors aren't crossed anywhere in the harness (and/or have you tried swapping them)? I'd also give the B2 connector second look based on its behavior in the first log.

For reference, some older threads with similar problems (and solutions):

https://forum.hptuners.com/showthrea...TFTB2-negative
https://forum.hptuners.com/showthrea...different-help

[Takid455]

Addressed the issue. Nothing to do with car, mechanicals or electronics. All that is good. Had to do with reassigning the injectors to each bank being this engine has a different firing order than the LS. Trims are very close and along the same path now.

[anniversaryss]

What kind of vehicle? I was gonna say injector bank assignment but i had no idea what vehicle. It was the same thing i had to do with my lt1

[Takid455]

Intentionally kept vehicle/ engine out as I have learned that when asking questions/ seeking help, if the application is anything from standard, it can be a ghost town with getting assistance. This is an LS ECU running a traditional Pontiac engine with coil on plugs & multiport. This particular issue was platform related so it may have helped.

Hoping to take the car out for a spin and see how it acts in closed loop. Been running open loop up to now.

[anniversaryss]

Intentionally kept vehicle/ engine out as I have learned that when asking questions/ seeking help, if the application is anything from standard, it can be a ghost town with getting assistance. This is an LS ECU running a traditional Pontiac engine with coil on plugs & multiport. This particular issue was platform related so it may have helped.

Hoping to take the car out for a spin and see how it acts in closed loop. Been running open loop up to now.

Well if you noticed in my signatur i do not run an ls motor but an ls pcm.

Typically running the pcms on older motors require a rewire and bank reassignment. The tuning ideas are the same. But also leaving out very pertinent information may not be. Beneficial for you in the long run.

As i stated, had i known the motor i may have said somthing sooner.