Help With Tuning, novice here

Combo and a little background: 07 Trailblazer SS, aluminum 6.0, stage 2 cam, specs unknown but imagine around 224,228 @ .580, Long tube headers, full stainless exhaust all the way out the back with 2 small cats (aftermarket system installed by someone else), front 02's are 6 to 8" from collectors, rears are turned off in tune. Truck showed up with exhaust leaks everywhere and bad 02's. Front 02's replaced with bosch, exhaust system was taken apart and all leaks fixed. new tr55 plugs, msd wires, all coils were replaced with another set of oem coils.

I am not a stock ecu tuner at all, I know just enough to get myself into trouble. I do however tune holley, fueltech etc. so Im not totally illiterate on the subject. I have a guy that put a tune on the ecu but has since flaked on me.

Problem: truck runs fine and 02's are even at .400 or so when cold. Once running a couple of minutes I believe its entering into closed loop and both 02's start fluctuating from 900 to 40s causing short and long term fuel trims to swing from dead lean to rich. Attached are log of the problem and tune, any help of course is appreciated. Lol, winner will be compensated.



Attachment 155279Attachment 155280

Either O2s or injectors are crossed bank-to-bank. And no Bosch O2s in a GM, ever.

Yup, someone's got this pretty jacked up. Part of the problem is being focused on WBO2's for stand alones then having to go back or switch back to reading NBO2's but, tuning is still tuning no matter what platform you use/like.

I'm not fluent in Gen 4 stuff at the moment but the first few things I notice is the BRAF is likely too high. The idle spark adaptives are way too aggressive for my taste. The idle spark table has a cliff built into it. There is a definite issue around the O2s' reporting or something causing an AFR issue. They do seem to start out off line (like not warmed up yet), then around 30 seconds in they start to separate. As soon as it goes closed loop things start to get even more separated, they cross over at one point around 47 seconds in and go complete retard after that. B2 goes full rich and B1 goes full lean. More later.

The more fuel it pulls from one bank the leaner that side gets, and the more it adds to the other bank the leaner it gets. This is the textbook example of what it looks like when the B1 O2 is plugged into the right side and the B2 O2 is plugged into the left side.

Quote:

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Originally Posted by Joshw817

Combo and a little background: 07 Trailblazer SS, aluminum 6.0, stage 2 cam, specs unknown but imagine around 224,228 @ .580, Long tube headers, full stainless exhaust all the way out the back with 2 small cats (aftermarket system installed by someone else), front 02's are 6 to 8" from collectors, rears are turned off in tune. Truck showed up with exhaust leaks everywhere and bad 02's. Front 02's replaced with bosch, exhaust system was taken apart and all leaks fixed. new tr55 plugs, msd wires, all coils were replaced with another set of oem coils.

I am not a stock ecu tuner at all, I know just enough to get myself into trouble. I do however tune holley, fueltech etc. so Im not totally illiterate on the subject. I have a guy that put a tune on the ecu but has since flaked on me.

Problem: truck runs fine and 02's are even at .400 or so when cold. Once running a couple of minutes I believe its entering into closed loop and both 02's start fluctuating from 900 to 40s causing short and long term fuel trims to swing from dead lean to rich. Attached are log of the problem and tune, any help of course is appreciated. Lol, winner will be compensated.



Attachment 155279Attachment 155280

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I do a absolute ton of TBSS stuff.

These are easy to cross the front o2 sensors. That is about certain what is going on with this. We made this graphic cause we run into it with customers all the time

https://www.pcmofnc.com/2020/04/08/c...r-information/


I do remote tuning and can likely get you straightened out in a few revisions. We make a bunch of products for the Trailblazer SS like fan kits, intakes, transmission coolers, etc.

Oh well, guess it wasn't THAT important?

I'll get with you soon. Gonna switch 02 harness and see what happens. I had to put this thing on the back burner for a mnt.

Thank you