what could cause idle to drop low and not shoot back to normal

[Crunkmaro]

its not idle surge...the idle is set at 900. i've noticed the issue last couple days (<30 degree temps) that sometimes (haven't quite figured out the parameters in which it occurs) the idle will drop to 800, not surge back up, and then when i am at a complete stop, the idle bounces (still under 900) and then the car wants to stall.

it hasn't happened at all before, and lately i've been using my heat...so maybe i'm thinking that theres a table that adjusts airflow or spark with the heat/defrost on?
so i'm going to try and drive without utilizing the heat/defrost/ac and see if the problem still occurs

if it still occurs then i'm assuming it may be an issue with the converter sticking after lock-up has been acheived and not releasing while slowing down.
so i'm going to try and drive in D (not D-box) so the car doesn't lockup and see if thats the issue.


also...sometimes the car will save itself from stalling, sometimes it won't. when it doesn't, and the car dies, after restart, everything is back to normal.


interesting conundrum.

[joecar]

Post tune and log files.

[5.7ute]

X2 on the tune & log files.
Since the heater & A/C share airflow tables but have a different load on the engine they are quite tricky to get right. B4328 can be fudged to prevent the airflow learning too low while you sort it out.

[macca_779]

Add 1.5 grams to desired airflow

[Crunkmaro]

i haven't done a log file since the issue started...i will get one tomorrow (1 with transstates pid file and 1 with calc_vet tuning file)

attached is my tune:11162.tun


before i start messing with airflow values, i'd like to make sure the issue IS related to airflow (which i really think/hope it is). i'm going to go for a drive w/o using the defrost/heat/air and see if the issue occurs, if it doesn't i'm going to start looking into possibly redoing my idle airflow tune since the temperature difference since the last time i did it is more than 60 degrees (F of course)

[Crunkmaro]

edit: problem popped back up

of course it happened when i wasn't logging. seems as though it only happens when
1) heat is on
2) i've been sitting for extended periods of time in traffic
3) there is a idle flare before the issue starts happening
4) it doesn't go away by itself unless i turn the car off and turn the car back on...ie it won't stabilize byitself



next step: add to b4301 and b4302?



upped the idle speed by 50 rpm vs in gear a/c off
problem doesn't seem to pop up.

granted...it will probably happen again after a couple months...seems as though the car is perfect the first 100 times i drive the car, but then stuff starts going haywire. weird.

also logged TCCstates to monitor TCC application, it releases when its supposed to (vss and brake switch and TPS position).

damn gremlins.