[tta1456]

IIRC it was either a simple enable/disable setting or it was an enable/disable by temp threshold setting for it.

What you posted doesn't look quite right as I don't remember it being under the SOI injection timing tables section and I know I did not have to mess with the start of injection timing for split pulse mode during cat lightoff, but my memory may be wrong as it's been probably 2-3 years since I last messed with it.

Just did some internet searching, and I found a few posts on the HPtuners forum saying that the cat lightoff enable/disable parameter may have been removed from more recent versions of HPtuners. As the EPA keeps threatening (and serving) lawsuits and big fines against tuners and tuning software writers when it comes to disabling emissions related features, the tuners keep removing emissions-related parameters from their software to avoid getting sued, so often times any new software release ends up locking you out of parameters you used to be able to see and change.

When HPtuners and EFIlive started removing specific emissions related tables and parameters from their software after the EPA shakedowns started several years ago, I stopped updating the software and firmware. While I can't tune the latest vehicles with the older software, at least I still have full tuning access on the older vehicles.

I'll look in HPtuners when I get home for the exact parameter I changed. Hopefully it's still available in whatever version of the software you have.

 

[tta1456]

My memory was correct, it's an enable/disable by temperature parameter.

Just change the temps to a range that cat warmup will never be active.

 

[FL103Dave]

Thanks for the info, I think that option isn't avaiable in the version of software I have. I have disabled the Rumble Start, but turning off the cat light up would be a benefit ass I don't have cats and it just makes the exhaust sound raspy on start up.

 

[tta1456]

If you can't see that parameter chances are HPtuners did remove being able to alter catalyst warmup from the newer software versions... that sucks.

It probably won't work for reasons of program version vs file version incompatibility depending on when you saved your stock tune file, but you might want to try downloading and installing an older version of HPtuners (say around 2019ish?) and see if you can open and resave your tune with that older software after changing the catalyst warmup parameter.

I believe there are a few people out there you can send your MPVI to and they can roll back the firmware on it by bench flashing it; then you can go back to the older hptuners software with full parameter access. Not sure how much that costs, or if that would be worth it for you.

Another option, provided your tune isn't locked-- find someone with an older MPVI/MPVI 2 with the older firmware and software that allows editing of cat warmup, have them read your current tune and then resave your tune with cat warmup disabled, and then reflash that tune with your current licensed MPVI. AFAIK the new software/firmware only disables being able to see and edit certain emissions related parameters in the tune and will not change the parameters of an existing tune you import, even if that tune contains changes to tables that are no longer accessible. After that you can then reflash the new tune with cat warmup disabled with your MPVI so you don't have to pay to license your VIN on the older MPVI you used to read and edit the tune.

EDIT: sent you a PM with something that may work for you...

 

[Jantzen]

The LF4 engine in an ATS-V does not have cylinder deactivation, thus, there is no "exhaust flow control" valve in the ATS-V exhaust system. Actually, you can see that for yourself simply by looking under the car at the exhaust system.

Operation of the tail-pipe valves on an ATS-V cannot be "personalized". On an ATS-V there is no menu selection for: settings>driving mode>engine sound management.

I believe you can if you press the home button on the cue then go to settings. There you can chose exhaust note, steering feel, and suspension set up. I believe it sets as your default until you choose another setting. I could be wrong about it being set as your default but if you press the home button again then settings the choices you made earlier are still selected. Oh and I am speaking from my car a 2017.

 

[bleu18v]

snip Oh and I am speaking from my car a 2017.

my '18 as well
sport and track settings the valves open @2k RPM, tour mode 4K. Definitely hear them opening/closing with throttle

 

[BigSteamer]

The valves operate off two tables in the CCM (chassis control module). There’s a table with rpm thresholds and another table with throttle positions. The tables reference each other and tell the computer when to open the valves. The valves can only be open 100% and closed 100%. They cannot open 25%, 50% etc.

There’s actually a third table called rumble start that dictates if the valves will be open for the first 3-5 seconds of start up. The rumble start can simply be enabled or disabled (valves open or closed). Factory calibration is open valves on start up in all modes for the first 3-5 seconds. If you’re looking for a stealth/quiet start you can disable the rumble start for any individual mode and eliminate the start up bark.

The valves in tour and snow mode operate identically. The valves in sport and track mode operate identically. In all modes the valves will always open at 3500 rpm regardless of throttle position or gear.

Tour/snow have the valves closed at all times in all gears except: When 3500 rpm is reached in any gear regardless of throttle position or when 100% throttle is used in any gear.

Sport/track have the valves open in gears 1-4 regardless of throttle position or rpm. Valves are closed in gears 5-8 unless 3500 rpm is reached or 100% is used.

The CCM can be licensed and completely modified with HPtuners but it requires 3 credits. If you do this just remember to not increase the rpm threshold of 3500 rpm for when the valves open. I imagine GM designed the system that way to prevent back pressure issues. Increasing the threshold above 3500 rpm (delaying the valves opening until 4500 rpm for example) could cause performance issues at minimum and damage something motor related at the worst. If you have aftermarket exhaust parts, particularly a loud exhaust, modifying the exhaust valves may be of interest to you.

 

[-Op-]

The valves operate off two tables in the CCM (chassis control module). There’s a table with rpm thresholds and another table with throttle positions. The tables reference each other and tell the computer when to open the valves. The valves can only be open 100% and closed 100%. They cannot open 25%, 50% etc.

There’s actually a third table called rumble start that dictates if the valves will be open for the first 3-5 seconds of start up. The rumble start can simply be enabled or disabled (valves open or closed). Factory calibration is open valves on start up in all modes for the first 3-5 seconds. If you’re looking for a stealth/quiet start you can disable the rumble start for any individual mode and eliminate the start up bark.

The valves in tour and snow mode operate identically. The valves in sport and track mode operate identically. In all modes the valves will always open at 3500 rpm regardless of throttle position or gear.

Tour/snow have the valves closed at all times in all gears except: When 3500 rpm is reached in any gear regardless of throttle position or when 100% throttle is used in any gear.

Sport/track have the valves open in gears 1-4 regardless of throttle position or rpm. Valves are closed in gears 5-8 unless 3500 rpm is reached or 100% is used.

The CCM can be licensed and completely modified with HPtuners but it requires 3 credits. If you do this just remember to not increase the rpm threshold of 3500 rpm for when the valves open. I imagine GM designed the system that way to prevent back pressure issues. Increasing the threshold above 3500 rpm (delaying the valves opening until 4500 rpm for example) could cause performance issues at minimum and damage something motor related at the worst. If you have aftermarket exhaust parts, particularly a loud exhaust, modifying the exhaust valves may be of interest to you.

Really great to know, thank you!