Yes, I have used the search function.
Yes I am read the guides and watched the videos and thought I had a good understanding of what is going on with the idle routines for these trucks.
I just got done doing a 2013 truck with a cam and after fiddling with stuff it idled nicely no problem. It had a bigger cam than this one.
Engine
6.0
factory rectangle port heads/intake manifold.
longtubes
218/228 112+3 .525 .525
6l90e
in a factory suburban.
Issues:
The idle routine is adding air from a table and I don't know what it is. It ALWAYS idles high, by about 100 rpm. Also, it starts to oscillate and buck wildly sitting still. As I come to a stop, the tps percentage is appropriate for the engine load to keep it alive as I coast down. Right as I come to a stop everything is great before the VSS reads zero, then it tries to push the truck by adding a few percent of TPS and the rpms kick back up.
Another problem is the wavy idle. This is the same program i drove around with earlier today in heatsoaked traffic with the a/c on and it never bucked or hunted. Restarted multiple times. Tried warm/hot startup. Thought it was fixed, then on my way home it does it. Up and down, only with your foot on the brake, it almost dies or pushes you into traffic. The over/under rpm behavoir matches the front 02s perfectly, rich = high rpm, lean = low rpm. help!!!! in my old ways, I would command my own afr at idle or open loop just the idle but it seems its impossible with the e38!
Things Ive tried to do to fix wavy idle:
turn off integral air
turn down/dampen spark control
adjust VVE fueling for the appropriate area.
made sure MAF readings werent too off
turned dynamic air to 300rpm.
Make sure timing tables were kinda close for idle.
add lots of minimum air, it just hangs the idle for a moment and then drops then proceeds to hunt.
took away air. it just keeps stumbling and hunting then dies.
changed desired RPM range from 600-700-75-800 and it just seems the computer will not hold the TB still below 800 rpms, which is odd since I got the previous truck with a seemingly similar operating system to hold it still no problem.
An important fact:
The ECT multiplier table is very small in this tune, and I have compared it with other factory 09 year models and they too use a .25 multiplier. while the previous truck I did had (what i thought to be) correct values of 1 after the engine was up to operating temperature.
I have included a log and the tune that seemingly lets it idle just fine, then randomly will start oscillating hard either 5 minutes after driving or 3 hours. Cant figure out what causes it.
Im down to start over again on one of these idle tuning guides, but every one i follow at the steps where it says "after you have your values and your idle is stable, blah blah blah" well my idle never is stable because the computer keeps trying to move the TB even after I zero out all adaptive air tables. there is something I am missing....
The log file:
towards the end you can see ass the VSS drops to zero the computer then starts adding tps percentage
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