6.2/manual stalling issues

[alexhr]

Hello and thank you for taking the time. Please be easy on me..... Trust me I have tried prior to this post and I am new at this .

I have a 6.2 iron/ NV3500 setup (don't judge, it will change to T56 eventually LOL), it was originally auto 4L60, I've been having issues with stalling coming to a stop with both setups, I didn't make much of it then given I was going to swap to manual, but now I just cant get this correct. I purchased the tune via email from Michigan MotorSports, and other than the stalling issue everything else works as it should... i think. I did perform segment swap from manual OS.

My son and I have been working on this project close to 2 years now and don't have but 400-500 miles on the build, currently breaking in rear end.

I have attempted to increase idle RPM which helped a bit but still found issues while running with a moderate throttle request when coming to a stop it tries to stall then recovers drastically..... I have played with RPM/timing/Throttle cracker/throttle follower/ throttle body adjustment screw...... same result. I have checked for vacuum leaks with same results.

I ask you kindly have a look and point me in the right direction, cheers.

10252023_6.2_manual_idle issues.hpl010252023_stalling issues.hpt

[edcmat-l1]

You have way too much idle air in it. That's causing the idle trims to pull a bunch of air.

This sounds like a swap vehicle. You should upgrade your OS to a 2002 F body 12212156. That OS has rolling idle tables and if you know how to set them up they will be the answer to your prayers. It'll cost you a couple credits but it'll be well worth it.

[alexhr]

That is correct sir, my apologies on my failure to provide cam information.

It has a BTR Stave 4 Truck cam. By idle air are you referring to Base Idle Airflow table???

[edcmat-l1]

That is correct sir, my apologies on my failure to provide cam information.

It has a BTR Stave 4 Truck cam. By idle air are you referring to Base Idle Airflow table???

Talk about leaving out the critical info. That is a huge leap from 6.2/manual stalling issues.

[alexhr]

Talk about leaving out the critical info. That is a huge leap from 6.2/manual stalling issues.

- Thanks for taking the time to help!

[edcmat-l1]

- Thanks for taking the time to help!

I guess you missed my first post.

[Alvin]

There is a lot that I can point out.. but the big things are this..

It looks like the VE table has just been hit with smooth button a few times but not actually tuned. This is critical for things like you are describing. Search failing maf and tuning SD. Poor fueling is normally the cause of idle dips. And those idle dips are often compensated with extra idle airflow. EVEN if the fuel trims look ok.. You will pass though rich areas as the engine decels causing a poor return to idle.


The desired idle airflow in this OS and early trucks will not take more than 28g/s or so.. I can't remeber the actual number but it is low. If you get above this number the IAC will go to 0. It behaves like it is a bug. For cars this limit is 39g/s.

I'd also increase idle to 800 RPM. That is pretty appropriate in a ?swap? vehicle and with a manual trans.