'05 CTS-V Dyno Results and Tune opinion

[SiriusC1024]

When DynAir starts biasing toward VE, and there is a large difference between DynAir and MAF, that's the indicator of incorrect VE. Yes there will be a difference during a transient. That's the whole point of Dynamic Airflow. It wouldn't be that much. The straight lines from 35-90kPa across the board say a lot.

In the trouble spot VE should be looking more like this:
estimated_VE.png

Than this:
original VE.png

Volumetric Efficiency Airflow isn't reported on Gen 3, but DynAir will equal that when in SD mode.

Nevermind about the tuner. To address OP's problem this would be one of the things that would happen.

[BuiltLifestyl3]

Ok. I've gathered all of your guy's points and here's what I have to say:

1) Idle...Yes idle setpoint is a little high, but when one of you mentioned the dip at idle...it was probably from the instability during a take-off and being a manual car. The idle always remains steady. I never see or feel any dips just idling. Now, when I'm coasting to a stop in neutral, the idle return will jump and "float" around 1000RPM for a couple seconds, then fall down to the idle setpoint. I guess in this instance, it makes it fairly smooth when I throw it back into a gear to make a turn after coasting through a turn lane to the stoplight while it's "floating" and no surging ever occurs. Now, I originally had a tough time sorting out the idle immediately after doing the cam swap. Even after rewatching videos online over and over again. I couldn't quite get the spark-in-gear quite right along with the base-running-airflow. I set it to about 900rpm idle and threw 28 degrees timing in there and multiplied the stock base-running-airflow by 1.3x and left it. All that was enough to get it running and driving without having to help it with my foot. It was enough to get it to the tuner on its own. I logged a few drives before going to the tuner and while heading there...fuel trims were all a little high on the low end...ESPECIALLY idle. Taking off from a stop usually was alot worse than it is now and it would surge at times and kick my ass. If I was to go back now and put the idle setpoint back down to 800RPM...I'll probably have a hard time getting it to behave as I did before. That a risk I don't think I want to take. I'm not sure why I struggled with it. I guess it's the ADHD not allowing me to think critically.

2) Fuel trims...I'm mainly concerned for the gas mileage. Yeah, it's a mid-size cam, but it's dropped more than I anticipated, unpredictable, and the logs show the obvious cause. ---I'm not constantly beating on the car--- It will decrease slowly the more I'm at idle. Never was like this before when I tuned it before the cam and had LTFTs at +-5%. Gas mileage only decreased if I've been beating on the car for the day. I'm confident I can do some adjustments. I wonder how the LTFTs would look if I turned them on...

3) VE...the chart and graph are indeed very smooth and aesthetically pleasing, but the general consensus from you guys suggest that I go through and do some SD tuning and log the errors and adjust. Man, see, I can't see them ever dialing it in on a dyno and just doing a few pulls. MAF, sure, but VE, no. That takes time. I know from experience. As I had said, they were over and done within 2 hours. By the time I got there to pick up the car, they already had another vehicle on the dyno doing pulls. It was right before they closed up for the day. I thought I was gonna be the last customer for the day, with there being only a 3 hour window from me dropping the car off to the time they're scheduled to close up shop. And if that was the case, you would think they'd have more time to triple check their work and do any necessary polishing. Clearly not.

4) As SiriusC 1024 had suggested at first, I will change the high-rpm-disable to 4000 and turn the LTFTs on. Seems the least I can do at the moment for observation. I honestly wanna say taking off from a stop needs the most improvement, from just a DRIVER'S perspective. I feel like I can't take anyone in the car with me until it's addressed.

5) I'm due for emissions and I'm catless. The monitor readiness of all are showing "ready" except the evap system. I'm very surprised to see the catalyst readiness is ok when I'm indeed catless. The evap system I have no clue on. I did get a DTC after getting the car back from the tuner P1626, but never had an issue with what it's calling for. No theft problems. Cranks and doesn't ever die.

[SiriusC1024]

Add to that injection timing and running the SD OS.

To your second point, you may have to adjust O2 PI settings. Easier to tell when fuel trims get closer.

[04silverado6.0]

I cleaned up a few things that should help idle and smooth things out. Give this a try.

[BuiltLifestyl3]

I cleaned up a few things that should help idle and smooth things out. Give this a try.

Ah, I see you made changes to the throttle cracker, setpoint, in gear timing, smoothed the high octane table, and a couple other things. Yeah, I'll give that a try right now.

Btw here's a log I just did a little bit ago after turning LTFTs on and setting high-rpm-disable to 4000. Very interesting difference.

24-04-13 12-13-46.hpl

Also, what do I do to "add to the injection timing"?

[04silverado6.0]

Ive already adjusted injection timing. After the ve and maf are fully dialed in you will adjust in small increments to find the most negative(rich) fuel trim. It is probably set close enough to leave it alone. I did not use a spreadsheet or anything, just made a good guess. Your fuel trims actually do not look horrible, i do not re-enable ltft on tunes. I go by the wideband and get the error i want and leave ltft off. Also, there is no law stating high rpm disable needs to be 4000 rpm. I usually set it around 2600-3200 or slightly above stall speed. Depending on your converter you may be into steady state well before 4000.

[BuiltLifestyl3]

Ive already adjusted injection timing. After the ve and maf are fully dialed in you will adjust in small increments to find the most negative(rich) fuel trim. It is probably set close enough to leave it alone. I did not use a spreadsheet or anything, just made a good guess. Your fuel trims actually do not look horrible, i do not re-enable ltft on tunes. I go by the wideband and get the error i want and leave ltft off. Also, there is no law stating high rpm disable needs to be 4000 rpm. I usually set it around 2600-3200 or slightly above stall speed. Depending on your converter you may be into steady state well before 4000.

Your adjustments helped alot! Two things though. One being the rpms shoot down a little too quick when changing gears. It's a manual car. It feels like it's taking a toll on the transmission. There's more wind-up in the driveline. It's like the car wants you to shift very quickly, which is not my forte. The feeling isn't terrible, but it isn't good either for longevity sake.

The second thing is if it's thrown into neutral to quickly while coasting to a stop, the idle dips to around 500RPM for a second and then hits the setpoint. That started happening towards the end of the log.

[BuiltLifestyl3]

The tuner mentioned my wideband shows 3/10ths too lean. Wideband error calculations for running without LTFTs would be a little off. So I wouldn't really count on it.

[04silverado6.0]

See if this is any better.

[BuiltLifestyl3]

See if this is any better.

A little better. Satisfactory now, I must say. I'll call it good and leave it alone at this point. Thank you a ton for even doing those adjustments for me. I wasn't expecting someone to just jump in here and do it.

[SiriusC1024]

When the VE table is right it'll get even better. Here's a continuation with the SD OS and setup to tune the VE table. If you'd like, write entire, use VCM Scanner to clear LTFT's, the log it.

[LS ROB]

I'll slam it all day, and I'll fix it for free.

This is the best comment i've read all day! Having an absolute cackle right now!