Cam/ProCharger idle issues

[1 Slow GTO]

I'm still rather new to LT tuning, and am at my wits end with this car. 2018 1LE Camaro, healthy cam (227/242 .637/.628 115LSA +6 advance), P-1X ProCharger with the "stage 2" intercooler and race bypass valve, DStecks baro breakout harness, ZR1 MAP sensor, longtubes, no cats, and MBRP exhaust. I've tried what The Tuning School suggests for idle parameters, as well as gone up and down with the external load, limit offset, and speed control reserve tables, and played with immediate and predicted speed control and I cannot for the life of me get this car to idle without surging. I've managed to get it to where I can at least drive it to start dialing in the VE tables and not have to worry about it dying, and once it's moving the car actually drives quite well. Tried settings all over the place, plus tried some from other LT tunes I have/found on here in so many different combinations I've probably taken a years worth of life off the starter.

Any and all help/tips/tricks/suggestions/etc to get this thing idling steady are more appreciated than y'all will ever know - I have a week to get this car lined out before it leaves for SEMA

[SultanHassanMasTuning]

you need to work on your VTQ tables. while logging your TQ ideally your torque should be around 0

[1 Slow GTO]

Haven't done much with virtual torque except for raising it to cure throttle closing issues. So I need to mess with it around idle to try and get it close to commanded? Also just realized I'd switched configs to do some diag the other day and didn't have torque logging in the one I posted...fml

[Ghostnotes]

I have the books and what I can say is it is not a how to, but more of a guide as in it will get you close. In the end I had to watch my trims and timing(mostly) after I got it to the point you are at. My cam is in the neighborhood of 238/244 64x/64x 112 or 113 with a YSi V7.

Start with the MAF tuning only for idle and part throttle first. Following what the books say in the setup, watch your fuel trims and timing(stay out of the ingle digits on timing).Once your trims are within 5 to 7% and you get your timing above 10*(you might have to tweak your torque tables a little here to help timing), start working the torque tables one by one. You will see changes to your trims and timing by working the torque now by themselves. I get idling good HOT first, then work on the cold starts.


This has worked for me and I'm still learning. As far as doing the hot first, I'm sure after a few more I will be able to get the cold starts dialed in first.

[ZeroBoostBuick]

What Ghostnotes said is good stuff.

[verocity]

You could setup a graph to log engine torque against the airmass in the virtual torque tables and average your results filtered by each spark amount.

What engine torque is the right one though? Delivered? Cmd? ..

[LSChev]

Ghostnotes, could you expand on what you mean by tuning the torque tables one by one? I am familiar with changing the tables for full throttle but have not had to do much at idle. I am working on a TT 396 LT1 that I have been able to get idling decently but no matter what I do it always wants to run 0-5deg of timing.

Thanks!

[Higgs Boson]

why would an ecm pull spark? maybe to reduce torque? what could we do to correct that? when the car is running low spark at idle where is the throttle blade? why? hmmm.....discuss. ;-)

[LSChev]

Thanks for cryptic response Higgs haha. I have been able to get the throttle blade to be pretty stable. approx 20% according to log. This truck has a lot of complexity going on.. lingenfelter injectors, cam, lt4 tb etc.

When it is struggling to get timing at idle it is also struggling to reach commanded idle rpm. Once every 10-15secs it will try to idle itself up by adding timing and when it does this everything looks good. But then for whatever reason it dumps it back to around 2deg.

Edit: I should mention I also have the tuning books but we all know how useful they are. Not much specifics in terms of cam idle pointers.

[Wheeler]

Thanks for cryptic response Higgs haha. I have been able to get the throttle blade to be pretty stable. approx 20% according to log. This truck has a lot of complexity going on.. lingenfelter injectors, cam, lt4 tb etc.

When it is struggling to get timing at idle it is also struggling to reach commanded idle rpm. Once every 10-15secs it will try to idle itself up by adding timing and when it does this everything looks good. But then for whatever reason it dumps it back to around 2deg.

Edit: I should mention I also have the tuning books but we all know how useful they are. Not much specifics in terms of cam idle pointers.

What tuning books do you use ?

[Ghostnotes]

Ghostnotes, could you expand on what you mean by tuning the torque tables one by one? I am familiar with changing the tables for full throttle but have not had to do much at idle. I am working on a TT 396 LT1 that I have been able to get idling decently but no matter what I do it always wants to run 0-5deg of timing.

Thanks!

I have been busy lately with work but you want to basically set a "spark minimum" for your idle. I set mine around 8 to 10* This will affect your torque and airflow but is a good starting point so far for me. There a few torque tables (will have to check which ones again) the help with idle. Basically if you can not get your timing above ...say -2* at idle, start reducing your torque. It's a little foggy and will recheck which tables since my car has been up on racks for 3 months now.

But in a nutshell I have.
1. get your fueling/airflow correct MAF only HOT.
2. Timing, which can be influenced by torque AND air( which affects torque/throttle position...kind of chicken and the egg here)

This has worked for me and my cam is even larger and I can idle at 700rpm. I have a short video of it in my early tuning stage for reference.



https://www.youtube.com/watch?v=nye3noma_Rc

[LSChev]

What tuning books do you use ?

I have the "GM Gen V Tuning using HP Tuners Software Level 3 Learn-at-Home Course" from the Tuning School.

Thanks Ghostnotes,
Okay, I have set my minimum to 0. I will try raising that to 8ish. Generally I am able to get these cars working without messing with the min timing but this is a more involved build than any of the others I have done. I have played with the VT. Usually I set my axis to exactly what needs to be changed and make small changes from there. This one is being a pain though.

I am also having an issue with cold start SOI. I will make another thread for that.

[Ghostnotes]

I have the "GM Gen V Tuning using HP Tuners Software Level 3 Learn-at-Home Course" from the Tuning School.

Thanks Ghostnotes,
Okay, I have set my minimum to 0. I will try raising that to 8ish. Generally I am able to get these cars working without messing with the min timing but this is a more involved build than any of the others I have done. I have played with the VT. Usually I set my axis to exactly what needs to be changed and make small changes from there. This one is being a pain though.

I am also having an issue with cold start SOI. I will make another thread for that.

It will try to fight that 8* timing if your air/torque is off. If it does, try adjusting one and if no change try the other. I'm not in front of my laptop(at work) and the air/torque reference is just general. Meaning I would adjust one set of rules first (air) and if no change, try the torque tables. In the end your timing and fuel trims will tell you if you are on the right track.

[LSChev]

It will try to fight that 8* timing if your air/torque is off. If it does, try adjusting one and if no change try the other. I'm not in front of my laptop(at work) and the air/torque reference is just general. Meaning I would adjust one set of rules first (air) and if no change, try the torque tables. In the end your timing and fuel trims will tell you if you are on the right track.

Thanks I will give it a shot tonight.

[32vape]

Go back to stock with all the idle torque settings and work on the virtual torque tables. Adding to the idle torque reserve will make the idle unstable and the car will surge and jump. Stock idle is 20-30 lb/ft. With a cam, the airmass and map are higher which raises the calculated torque per the torque coefficients. It needs to be the opposite. You have less torque at idle with a larger cam. Tune the MAF then the VE to get you air model correct then tune the virtual torque.