2008 TBSS tuning beginner trying to figure it out

[WPAS]

Okay, so... I am VERY wet behind the ears with tuning but... I have done some looking and saw some do's and some don'ts. Run down of the vehicle;
2008 Trailblazer SS purchased 2 weeks ago. Mods that I knew were there - eFans (derale?), CAI (unknown name... open element). That is all that I know was done. Yesterday I installed LT Headers and ORY. Prior to this the TB was getting lean codes when pushing it, I saw multiple places that this is common with a CAI and no tuning. Pair that with my header install and that made me pull the trigger on getting this old girl dialed in. So, I will attach my file if I can figure out how to. I to this point have the MIL shut off, the COT shut off and I think that is all... looking for some direction or pointers on where to start with the MAF tuning. I've been watching GRG on YouTube trying to figure a few things out but would really appreciate some assistance from personal experience.

Thanks guys,
Kyle
TBSS Initial Cat Delete.hpt

[FASSTRUK]

First step is to install a wideband O2 sensor. VVE tuning is tuned using it. Maf is tuned with it and the narrow bands.

[HawkZ28]

You can do both MAF and VVE at the same time with NBO2's.

https://forum.hptuners.com/showthrea...ation-for-gen4

[Tunercharged]

First step is to install a wideband O2 sensor. VVE tuning is tuned using it. Maf is tuned with it and the narrow bands.

I started tuning with HP Tuners at the beginning of this year. You can tune with O2s to a certain extent but you will have a much easier time tuning with a wideband. It was totally worth it to put one on my truck. I had to remove part of my exhaust to weld the bung where I wanted it but I’d do that to any vehicle I would ever consider tuning, so I’m recommending it to you. First step for sure.

[blindsquirrel]

If the narrowbands will be in charge of closed loop fueling after tuning is 'done', why should they not be used to tune the closed loop fueling?

[Tunercharged]

If the narrowbands will be in charge of closed loop fueling after tuning is 'done', why should they not be used to tune the closed loop fueling?

I think that tuning that closed loop range of AFR can be done with NB O2s but for simplicity a wideband gives me the whole fueling picture completely whenever I record a pull. For a very novice tuner such as myself I have saved a lot of time by using a WB because it just made the whole tuning procedure easier for me to grasp.

[blindsquirrel]

Well the NBs are more accurate at finding stoich. Widebands have a linear response, NBs definitely do not.

[WPAS]

Update - FINALLY got a wideband installed. Someone has ABSOLUTELY been in here before and I think they knew less than I do. So... Cruising its around 16.6-17.2 mid pull looked like 15.4 and WOT was fluxuating around 15.3-15.4. I'm really wondering if I need to get a factory flash just so the base is there. The trans pressures are essentially maxxed out... I feel like it's pretty lean. Got a Dragy to see what it will do and with a "CAI", long tubes, ORY, Efans and whatever "Tune" is in it it's running a 14.8 @96 which is what this was rated at stock. I'm working on getting some data driving around and getting tables populated, but all signs point to this running lean and needing fattened up. Is there anything obvious in the file above? I'm VERY wet behind the ears but also don't want to just jump in all by myself and fry an engine.

[blindsquirrel]

How is it that lean without the trims adding fuel to correct it? Or have you jumped straight to open loop? I think I'd confirm the WB and NBs agree while in closed loop first just to confirm the WB is reporting reality.

[WPAS]

Yeah, it's that lean... open loop even though it?d been running for a 45 min round trip? 👀🤷🏻*♂️

[blindsquirrel]

Your O2 Readiness ECT somehow got changed from stock -40 to 400. That's in the first (only?) tune file you posted.

[WPAS]

Your O2 Readiness ECT somehow got changed from stock -40 to 400. That's in the first (only?) tune file you posted.

Yeah, that's all I have at this point. So is the whole table need to be equal to -40, or is it a sliding scale? Reason I ask is the only thing that I personally did in the file above was kill COT and rear o2 codes... (I think)

[blindsquirrel]

Change log shows the readiness ECT thing got changed since the file was last read out of the ECM, and I'm assuming you didn't get a .hpt file from the previous owner, so that's been changed since you got it. Readiness ECT is for closed loop and downstream O2s are not used for closed loop on this, only for catalyst monitoring.

I fixed that, found some S2 DTCs that were missed, un-disabled the stock power enrich settings, and changed some catalyst stuff you don't have access to.
TBSS Initial Cat Delete - actual.hpt

[WPAS]

Thank you!!! I will say that is a significant difference from a dig! 🤣 I?m going to need some stickier tires - I guess it?s probably cold roads and cold tires lol! I?ll try to get some logs and adjust! It looks like LTFT was already starting to pick up in areas! Thanks again!

[WPAS]

So, last night I did a full rewrite to the original file and it ran its new PB? BUT something messed up and the vin didn?t copy properly so HP is saying I cannot tune on it? did I f**** the pcm?!