lean area around 2500ish rpms-2014 ctsv

Could the large swing in timing during shifts aggravate it? I don't know if it is running off the base timing chart or the idle spark advance/coastdown, but both were similar, and higher than a 2012 V cal that I had saved (supposedly stock cal). It is climbing to 48 degrees at start of shift, then dropping down to 18 before you get back on the throttle, then it jumps back up. The WB may read differently depending on the timing you feed it as well.

There was also a peak in the VVE chart at 2600 rpm from an older posting on this thread, with a bit of a valley before and after. VVE should be nailed down good before changing transients.

Quote:

---

Originally Posted by NotSure

Could the large swing in timing during shifts aggravate it? I don't know if it is running off the base timing chart or the idle spark advance/coastdown, but both were similar, and higher than a 2012 V cal that I had saved (supposedly stock cal). It is climbing to 48 degrees at start of shift, then dropping down to 18 before you get back on the throttle, then it jumps back up. The WB may read differently depending on the timing you feed it as well.

There was also a peak in the VVE chart at 2600 rpm from an older posting on this thread, with a bit of a valley before and after. VVE should be nailed down good before changing transients.

---

Yeah, i do believe my timing is slightly higher than a stock cal (in the low/mid load areas). That peak is there because the additional fuel needed at that point. Multiple guys with ctsvs and aftermarket injectors show this same lean condition. i know that lean area didn't start until i put in my Id850s injectors. Smokeshow pointed out that he thinks it's reversion in the intake causing incorrect airflow measurements by the maf. I'm still not sure how to fix it though

What if you logged VE airflow and Dynamic airflow (both in g/sec) and charted them side by side? My OS also has Mass airflow but I do not see it on yours. It can help to chart all 3 (or 2 if that is what you have available) to see how well they match. I know that you have MAF enabled immediately, but it still references VVE for transients.

Also, is it hitting DFCO? You cannot go by inj pw, at least on mine, as pw NEVER drops to zero on the scanner, even when in DFCO. You would have to log DFCO Active (Yes/No). Just to see if it is going lean during the shift due to that, or due to airflow modeling. Even if it is activating, you should still be able to step back into it without a hiccup, but it may point out an airflow error.

Quote:

---

Originally Posted by NotSure

What if you logged VE airflow and Dynamic airflow (both in g/sec) and charted them side by side? My OS also has Mass airflow but I do not see it on yours. It can help to chart all 3 (or 2 if that is what you have available) to see how well they match. I know that you have MAF enabled immediately, but it still references VVE for transients.

Also, is it hitting DFCO? You cannot go by inj pw, at least on mine, as pw NEVER drops to zero on the scanner, even when in DFCO. You would have to log DFCO Active (Yes/No). Just to see if it is going lean during the shift due to that, or due to airflow modeling. Even if it is activating, you should still be able to step back into it without a hiccup, but it may point out an airflow error.

---

Yeah i currently have them logged and they overlap each other pretty well...even at that 2600 rpm lean spot.

Made some changes. Retune your MAF as your injector data was off a touch.

Quote:

---

Originally Posted by GHuggins

Made some changes. Retune your MAF as your injector data was off a touch.

---

Thanks. the injector data was taken right from I.D. website. Are you referring to the IFR vs pressure delta?

I also noticed you changed the injection timing boundary angle. I thought that should only be altered when you get an aftermarket cam? I'm just trying to get a few more wrinkles for my brain!

I changed timing for you - you should like it better. The ifr was straight from ID's website - they may have altered it in the last couple of years - don't know. Also changed your PE fueling delay, transients, O2's and VVE based off of one I tuned years ago almost identical to yours.

I will also say your costing yourself about 20hp to the tires with the "test pipes". If you don't want cats, your better off to buy cheapo "if there is such a thing anymore" off road cats and then gut them. The "expansion chamber" gives back pressure somewhere to build right before that right angle turn the exhaust has to make.

Quote:

---

Originally Posted by GHuggins

I changed timing for you - you should like it better. The ifr was straight from ID's website - they may have altered it in the last couple of years - don't know. Also changed your PE fueling delay, transients, O2's and VVE based off of one I tuned years ago almost identical to yours.

I will also say your costing yourself about 20hp to the tires with the "test pipes". If you don't want cats, your better off to buy cheapo "if there is such a thing anymore" off road cats and then gut them. The "expansion chamber" gives back pressure somewhere to build right before that right angle turn the exhaust has to make.

---

thanks, I appreciate it. Just to confirm i will have to tweak the maf curve again since the boundary angle has been changed correct?

I didn't realize that about the test pipes...only reason I got them was to prevent melting the stock cats

Yes, you'll need to tweak the MAF due to the changed ifr and boundary.

Did extensive dyno testing on these back in the day - that's how I know about the "test pipes". They may even be causing a boost spike when you stomp it partially causing your lean condition or if nothing else making it worse.

Quote:

---

Originally Posted by GHuggins

Yes, you'll need to tweak the MAF due to the changed ifr and boundary.

Did extensive dyno testing on these back in the day - that's how I know about the "test pipes". They may even be causing a boost spike when you stomp it partially causing your lean condition or if nothing else making it worse.

---

Alright thanks for confirming. So just for my knowledge, what in terms of performance does changing the boundary angle do?

More torque and allows more timing up top

Quote:

---

Originally Posted by GHuggins

More torque and allows more timing up top

---

Nice, nothing wrong with that....lol. I did a quick log (maybe 10-15 min) and it looks like i need to pull a little bit of fuel out. Is that what you would be expecting to see? At least during CL..i haven't gone WOT yet. I"m going to during a good 30-45 min drive to get some good data though

Yeah, looks like the one I tuned was needing less from 11700hz down and needed a touch more fuel from there up a little ways.

Quote:

---

Originally Posted by GHuggins

Yeah, looks like the one I tuned was needing less from 11700hz down and needed a touch more fuel from there up a little ways.

---

Got it. Yeah, I went for a long drive yesterday and I needed to pull out just a bit (3-4%). Once I was above 10000hz it was pretty much spot on.

Quote:

---

Originally Posted by GHuggins

Yeah, looks like the one I tuned was needing less from 11700hz down and needed a touch more fuel from there up a little ways.

---

So i have the maf pretty maf pretty much dialed in other than this weird thing going on. I'm currenty maf only tune and at very little throttle inputs (sitting in the driveway and ever so slightly touching the gas pedal) it goes lean for a short period of time. Very light tip-in issue. It looks like the o2 sensors aren't switching at this time. Is there a way to get the 02s to switch in this area? happens at 2:26 and 3:02. This is very repeatable and isn't a random occurrence. Short log attached
Attachment 120466

Just lower integrator delay for that airflow area. You might also want to lower proportional delay settings too. That's if it's just an O2 related issue and not a transient related issue. Then if your Ethanol you'll want to advance injection timing 15 degrees back - that helps a lot with ethanol.

Quote:

---

Originally Posted by GHuggins

Just lower integrator delay for that airflow area. You might also want to lower proportional delay settings too. That's if it's just an O2 related issue and not a transient related issue. Then if your Ethanol you'll want to advance injection timing 15 degrees back - that helps a lot with ethanol.

---

Alright I'll try adjusting the delay settings for the 02s...nope, just pump gas here. Thanks for the advice

Quote:

---

Originally Posted by GHuggins

Just lower integrator delay for that airflow area. You might also want to lower proportional delay settings too. That's if it's just an O2 related issue and not a transient related issue. Then if your Ethanol you'll want to advance injection timing 15 degrees back - that helps a lot with ethanol.

---

So i decreased the integrator delay by 8% and if you go to the 3:00 minute mark it seems to have gotten worse...there is like a 6 sec delay before they start switching again. This isn't a major issue or anything but i'd still like to get it figured out

Attachment 120495

Quote:

---

Originally Posted by pannetron

My change didn't cure it but did reduce it enough to satisfy me.

---

what change did you do? Change your zones in the VVE?

Quote:

---

Originally Posted by sgod1100

what change did you do? Change your zones in the VVE?

---

Did you ever figure this out. Having the exact same issue with 13 CTS-V and id1050cc injectors. Only thing thats somewhat helped is spike the vve table in that area. Still has a slight spike but at least it doesnt fall on its face when cruising.