Like a Virgin - Tuning for the very first time

[Critter93]

Evening all,

Just getting into the tuning thing and have been stalking the forum for a while now. I think I am ready to make the leap and adjust the current tune on my 2011 CTS-V. Mods include:
AirRaid Intake
Griptech 2.35 upper (w/solid isolator)
ID1050 injectors
BMR reservoir tank
C&R intercooler
Varimax pump
TSP Long Tubes with hi-flow cats
Ballenger AFRv2 wideband
NGK plugs

I had the car tuned about a year and a half ago by a local tuner who did a fantastic job. I have been quite happy with the tune, but, that was before I had headers. As such he added a bunch of fuel to keep the EGTs down to save the stock cats. Now that I have the headers it is time to makes some changes (cause it is pig rich) and I figured it would be time to dip my toes in the water to start to learn. Attached you will find my tune (which I modified already to turn off the secondary O2 sensors) as well as three logs from today. The first one includes a short on-ramp pull and some stop and go on my way to work. The second one is short but was logged mainly to capture the very loud decel pop that now occurs with the headers, and the final one is me playing on the "track" with my buddy in his new GT350. I appreciate any inputs/advice and I will be working this over the weekend and the coming weeks...probably going to take it nice and slow.

Thanks ahead of time.

[Critter93]

Final log didn't load for some reason, if anyone wants it let me know and I will figure out how to add send it direct

[5FDP]

You're going to need to disable the post o2 sensor test and the cat test itself in the engine diag's exhaust tab. As well as disabled the COT (cat over temp) in the fuel > temp control tab.


The commanded fueling is not exactly rich but it surely is no where close to the actual fueling, and that is what really matters here. I saw the commanded be at mid 11's but the actual reported by the wideband at 9.00 to 10.4, which is a wide range and not close at all to the commanded. That could surely be a cause for the massive amount of knock retard being reported in the logs, too much fuel can be just as bad as not enough fuel. It's robbing lots of power because of how much timing it's taking away.


If it was me I'd for the time being set it up to run a "MAF only" type mode to calibrate the MAF curve first using your wideband o2 sensor. The VVE portion can be done separately later on.

The objective is to get the calibration setup for a MAF only open loop tune where you have closed loop and all o2 sensor control disabled. Like long term fuel trims and short term fuel trims. You will be creating a Lambda Error or AFR Error against the commanded AFR to see where and when the fueling differs from the commanded. The error that the graph creates can be applied to the MAF curve to fix the airflow model and get fueling in check.

There are several youtube video's as well as the VCM scanner section sticky pages that you can look at to see how to setup one of these scanner logs.

[Critter93]

5FDP,

Thanks for the recommendations and way forward! I will be working this over the weekend and will post an updated log/tune after I make my first round of changes for all to see.
Again, thank you for taking the time to provide me with your inputs.

[Critter93]

Well here is the tune I am running to get it to MAF only and make adjustments as well as the first log. Looks way off to me, but when I did the copy>paste special>multiply by % - half.....The issue I am running into is that it only gets richer every time I make an adjustment. What am I missing now?Caddy - MAFstep1.hpt19-10-15 19-49-18.hpl

[Dbell79]

You should probably check out the thread about "rich after reflash", more than likely that's whats going on.