Target idle.

[EagleMark]

ASDU is 525 stock totally warmed up in closed loop. If you can't get it that low just get it lower then that and stable.

Without looking at data it's a little harder. Drive around and get warmed up, turn off and cross A and B of ALDL plug, turn key on, unplug IAC, start engine and rev to 1500ish RPM for a minute to insure CL timer delay is met and O2 is warm and gone closed loop. Then set idle below 525.

[jameslleary]

Is that the minimum idle air setting, or the actual idle speed in drive(Target)?
Edit: never mind....i got it, thanks Mark!

[Scorp1us]

What is OL timer delay?

[EagleMark]

What is OL timer delay?

I made a mistake in that post above and will change it to CL where it says OL. (Closed Loop / Open Loop)

There's several OL and CL delays depending on the bin file. Some bins are OL idle and some are CL idle. So depending on the bin there is a delay going from CL while driving to OL idle. There is always a CL delay when started on these to insure O2 is warm enough.

[black dawg]

Does it have to stay in closed loop to set this min spec? I have never heard of setting the idle 100rpm lower than spec, is this actually needed?

[Scorp1us]

Hrm, yes, getting a vehicle into OL while warm and at a stop would be hard.

BD: yes, it shouldn't be in Open loop at all. in open loop it's not looking at the O2 sensor. But the reason why you set it to 100 less is that the IAC should be closed when you do this. Later when the IAC is partially open, it will be putting more gas in for the air coming from the IAC and will increase the idle speed. Then if you're worried about drive or AC being on, there are "bumps" to the idle for those.

[EagleMark]

Yes it has to be in closed loop for this procedure to work properly because the taget idle speed is set from the "IAC - Desired C/L Idle Speed" table.

It's not an idle setting, it's a minimum air setting. Your trying to get as much air past throttle blades as possible but still let IAC control idle.

Is it needed? Usually no. If your TBI system is stock with less then 125K miles it is probably fine, if you find your throttle sticking and jerks open when you hit the gas, but does not jerk open with engine off, then yes it's needed as the throttle shaft has worn and blades are not open enough. If a conversion to another engine it is usually needed. If your warmed up Closed Loop idle IAC counts are more then about 50 - 60 it is needed.

[black dawg]

OK, it must be lack of closed loop that is giving me problems. I just converted my 91 burb from 350 to 454, and have the 454 throttle body and prom. It goes into CL easy enough when you fast idle it, but falls out almost immediatly when it idles. Probably because of the open manifolds? Hopefully will get the exhaust finished up by the weekend.