Originally Posted by
Jim Brown
Hello,
It's not surprising that this thread is still going.
Earlier it was mentioned that there are various factory idle schemes not necessarily covered here.
Well I'm dealing with one of them, and I am hoping that there is a solution out there.
My engine runs dang near perfect except for one REALLY, REALLY annoying thing.
On coast-down, in gear, (or revving in park), with an auto trans, my IAC will go to ~172 counts ......,
( from 0 counts, which is where I want it to stay ), ( normal hot idle is ~40 counts ),
( transition to idle is normally seamless, short, and spot-on, in park or gear,
unless this ~10 second "cycle" kicks in, and is incomplete ),
( it sometimes kicks in randomly with closed throttle deceleration ),
( it seems like it may be an anti stall strategy ).
....... starting at around 1500 rpm, it will then hold that for around 5 seconds, then drop to
around 80 counts, for another 4 to 5 seconds, before dropping down to a normal idle.
This of course, means that I am fighting the engine with the brakes, especially when
the TCC is still in lock-up, ( which I want, usually ).
The truck will maintain 55 mph under certain circumstances, foot off the gas.
I've spent just stupid hours researching this with no joy.
I've massaged and manipulated every setting until I have no hair left to pull out.
This is also through many, many timing changes, anywhere timing can be adjusted.
AFR is a perfect 14.6 on wide-band O2 at all times, excepting warm-up and PE.
The only thing that seems to have had any effect is setting the "Base Running Airflow" down
to HALF of the stock numbers (from 40 to 20 lb/hr), this doesn't seem to be causing any
problems so far, with around 5 warm-up / start-stop cycles, but it's just less pronounced,
it still does the same ole sh*t, and this is NOT a proper solution.
I'm getting tired of this.
Is this a setting that is simply not accessible with HPTuners ???
I've tried every trick I know, and I have substantial tuning experience, and NOTHING will
make this completely go away, and I don't even have to fight with a huge cam, (stock).
PLEASE, tell me I've been stupid and blind, and all I've got to do is change one number.
There are some strange things you will notice in my tune if you look at it,
THEY ARE NOT THE CAUSE, this has existed since day one.