2006 Tahoe Cammed Idle Issues

[HKrue94]

Started tuning my Tahoe after a cam swap. 218/218 .500 Lift 111 LSA. Started with some baseline adjustments to get it running, and I'm starting my tuning process in Speed Density. Getting my VE table close, I'm noticing that my dynamic air versus desired air is somewhat close at operational temps. My IAC counts are in the 50-70 range, spark around 18 degrees. Then while idling in this state, my spark advance drops, my IAC counts go down to the 5-15 range and my desired idle airflow then sits at 5 g/s while my dynamic is still around 7-9 g/s. Below I'm posting my idle log and my tune. Any info of what is happening and how to fix it would be greatly appreciated!

2006 Tahoe Cam VE tune + Gear Ratio Adjust V2.hpt
Idle for new tune, wierd idle change.hpl

BTW, this change happens around the 3:20 mark (minutes)

[blindsquirrel]

There is no IAC in a drive-by-wire system. Make sure you aren't using a guide written for cable TBs, you will end up way way off in the Land of Confusion.

[HKrue94]

Thanks, I was using a guide that was for IAC. My next question would be, am I possibly adding too much air for this camshaft? stock file is 4.8 and i did 2.5 across the board. Does 5 g/s desired idle air seem too low? Or am I over thinking it?

[edcmat-l1]

I wouldn't worry about dynamic vs. desired. Your STIT is -.7 g/s which means you're pretty close.

[Alvin]

The idle airflow stuff will often not match up with dynamic or MAF Airflow. This is normal for GEN 3

You'll occasionally see the STIT's jump back to zero and then learn back to where they were. This is also normal.. Fuel trims will act the same way. Youll see them reset on thier own to zero periodically.

I like to set GEN3's up to be pulling 0.5 g/s out to give a little buffer. This will not be consistant. You just need to be in the ball park. Idle airflow is a coarse adjustment for idle. Once it is in the area spark timing will control the rest.

[HKrue94]

Which number should I log and use as a base for my BRAF table? Dynamic or Desired?

[Alvin]

Not a fan of either. I look at the corrections STIT and LTIT

[edcmat-l1]

Not a fan of either. I look at the corrections STIT and LTIT

Winner winner, chicken dinner. Tune your BRAF by error correction.