quick throttle drops RPMS to below desired

I finally got my truck tuned so there is no issue with the off idle to 2000 RPM drag (increased timing, increased fuel and airflow) so now on to an issue that was always present. When i give the truck quick throttle the RPM's drop down to 500 and up past desired and "hunt" for the correct idle. This also occurs when i come to a quick stop. After research I have found 1) adjust idle airflow under idle tab (I don't have this in newest HPT) 2) Throttle follower (thought it was just for hanging idle?) 3) Idle throttle Immed underspeed and immed overspeed (no clue on finding what these do) 4) VVE table decrease 400-1200 RPM 40-70 kPa by percentage (tried with no luck)... A lot of answers I've found are for gen 3 and older version of HPT. Any pointers for the direction I should try for adjusting parameters would be helpful. I will post a log this afternoon. 2012 2500HD 3/4 6.0L, TSP vvt1, JBA, flowmaster.

It sounds like it needs more air, can you post tune and log.

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Originally Posted by RySmDPT14

I finally got my truck tuned so there is no issue with the off idle to 2000 RPM drag (increased timing, increased fuel and airflow) so now on to an issue that was always present. When i give the truck quick throttle the RPM's drop down to 500 and up past desired and "hunt" for the correct idle. This also occurs when i come to a quick stop. After research I have found 1) adjust idle airflow under idle tab (I don't have this in newest HPT) 2) Throttle follower (thought it was just for hanging idle?) 3) Idle throttle Immed underspeed and immed overspeed (no clue on finding what these do) 4) VVE table decrease 400-1200 RPM 40-70 kPa by percentage (tried with no luck)... A lot of answers I've found are for gen 3 and older version of HPT. Any pointers for the direction I should try for adjusting parameters would be helpful. I will post a log this afternoon. 2012 2500HD 3/4 6.0L, TSP vvt1, JBA, flowmaster.

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Edit, view, advanced. Close program, re-open. You're only seeing a fraction of the available tables right now

Sounds like min air to me too, at least start there

Also look at the VVE table in the idle cells. This can cause the issues you mention as well.

here is a tune I readjusted some parameters increased idle throttle area, increased idle speed to 700RPM, which seems to do well with the TSP VVT1 cam. for the VVE table do I increase the numbers or decrease? I assume increase, telling the ECU there is more air entering engine.

So on my 2013 1500 5.3 i've been having the same issue, well after countless hrs looking and changing things around last night i downloaded another stock file and found out my o2's were way off alot which i've never changed, so i changed those this morning went for a 2 hr drive and now my truck is smooth as silk idleing and cruising, I would compare your's to another stock file and see if that's your issue as mine was from new.

I will have to look into the O2's, I will log them and see. Thanks

I helped a guy remote tune his sierra with same problem.

We found that the truck follower settings were terrible with a camshaft. I flashed in the entire chevy SS follower tables (rpm and airflow side, there are like 10 of them)

Try that. Can also add to idle and coastdown spark at the blip rpm as well as airflow. My tuning motto is always sanity test first, so make large changes to see if anything changes in the RPM drops. Then tune down from there.

Big Mike,

I have adaptive idle tab: follower underspeed, immed underspeed and Idle torque reserve tab: follower reserve.. its 2012 silverado 2500HD

Not sure, I never saw those settings. But throttle follower tables are the ones you wanna look at as they only come into play when you lift the throttle. If it's dropping like a rock, also check torque management spark in the scanner as it happens.

I had the same issue for a year. I have a Gen4 4.8 with a cam that has the same duration and lift as a LS3, just with a 112 lsa. I have the truck idle at 630rpms when warm. I tried all types of min air flow, coastdown, torque follower settings. I searched a lot of "coastdown" treads on here, picked and pulled info from each and here is what ended up working for me. I copy and pasted the following tables from a 2015 chevy ss stock file. Minimum air flow, baro multiplier, ECT multiplier, idle, coastdown, and torque follower. For Idle and coastdown i made the 0-1000rpm, 08-36 g area like 16-18? and smoothed. For the Min airflow I made 200-800 the same as the 0 rpm (51.4). Then my idle was actually hanging, and what I found that made the most change in the coastdown under 2000 was the ECT multiplier. The stock SS was more than double my truck. I ended up finding a happy medium that was a little less than double my trucks numbers. Hope that might help.