AEM Idleing

87targa

New Member
Nov 14, 2005
200
0
0
Utah
Need some help with idle. It seems to hunt after i drive the vehicle around for a while. the idle is fine (doesn't hunt) on warm start. I have know idea how to fix that. anyone have an idea?
 

87targa

New Member
Nov 14, 2005
200
0
0
Utah
it's the stock iac. i have tried adjusting the fuel from 60.9kpa to 21.6 kpa and between 400 to 1200 (ie 3x4 matrix) to have an afr of 14.7 or around there and ignition between that range of 12*. idle hunts. i then tried changing fuel and ignition cells 60.9kpa to 21.6 kpa from 400 to 1200 rpm to one value. idle also hunts. also tried setting the idle% vs target to reach the target idle. it reaches the target idle i drive around and then it hunts for the target. i can try to upload my cal file for you guys to look at if you would like?
 

Funkycheeze

Grease Monkey
Jul 3, 2009
163
0
16
Calgary
Check the idle dead band, should be +-50. Also 200ms reaction time for the motor is about right.

I find the idle to be alot more stable around 12.0 - 13.0 :1, and I overfuel a bit and use the O2 feedback to correct at idle.

Also, the % vs target should overshoot the idle thru its entire range by about 5%, so the program can then correct down to the desired idle, to prevent undershoots and the potential for stalling. The % target vs base should always be around -5 to 10%.
 

Enraged

A HG job took HOW long??
Mar 30, 2005
1,843
21
38
Victoria, BC, Canada
mine hot idles at around 13.7 at around 1000 rpm, with no idle speed control of any sort, so you should be able to get it to work.

from what I read on the AEM forum, the AEM can lose control of the stock IAC, apparantly it can think it's in one position, but it's actually in another, and it gets into a feedback loop and can stall out.

also, double check:
http://forum.aempower.com/forum/index.php/topic,13380.0.html
 

Flateric

New Member
Mar 26, 2008
946
0
0
Calgary, Alberta, Canada
3p141592654;1763610 said:
The stock ECU drives the ISCV stepper at 8ms intervals. 200ms seems ridiculously slow.


Idle feedback rate on mine has to be around 250ms in order to prevent overcorrection and causing swinging back and forth. Also should be mentioned that the OP is using a series 2 box with aem tuner, not aem pro.