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View Full Version : idle drops with defroster setting?

NOLAG
10-14-2011, 03:59 PM
so bsically as the title states ...my idle drops pretty low only on the front windshield setting with the blower on any setting from 1-4 ?any ideas?thanks!
2.5T_/<ouki
10-14-2011, 04:15 PM
How low is pretty low? Was pretty sure it is normal to see a bit of a drop
S14DB
10-14-2011, 04:18 PM
Check your IACV.
NOLAG
10-14-2011, 05:19 PM
well my iacv is blocked off i just did a ka-t setup..and its normal for it to drop on the normal blower setting with no ac?it drops about about 200 rpm's......iacv was acting up in the middle of boosting so i just blocked it off and cracked the throttle plate...now when my car is fully warm it will idle roughly at 900
cdlong
10-15-2011, 08:59 AM
The defroster kicks on the AC. There's a function somewhere (ECU, IACV not sure) to bump the idle back up to support the extra load from the AC, maybe that isn't working.
NOLAG
10-15-2011, 09:41 AM
The defroster kicks on the AC. There's a function somewhere (ECU, IACV not sure) to bump the idle back up to support the extra load from the AC, maybe that isn't working.

it does?wow didnt know that since its not like the ac light goes on or anything...what do you suggest me doing?isnt the idle suppose to go up a little when the ac goes on?
locoluna825
10-15-2011, 12:09 PM
THe IACV kicks up the idle for Alot more things than just your ac. It does have a dedicated soleniod on the unit to the AC. A certain amount of Drain to the charging system of the car will cause the IACV to kick in. Your blower motor will cause that. Also maxing out your wheel and causing the powersteering pump to stuggle will make the IACV kick on. It wont exactly bump your idle up higher. Maybe a little. ITs just there to compinsate. So whatever RPMS lost from these types of parasitic loss at idle it will try to compensate a normal of range rpm's during idle.

The defroster kicks on the AC. There's a function somewhere (ECU, IACV not sure) to bump the idle back up to support the extra load from the AC, maybe that isn't working.

Totally forgot about this too^^^^
cdlong
10-15-2011, 12:38 PM
It does turn the light on in some cars, I think my Outback does it. Anyway, either put the IACV back on or just deal with it. Stock idle is supposed to be 700 I think, so I'm sure you'll be fine.

In case anyone is wondering why the AC comes on with the defroster, it's so the air is dryer as it blows across the windshield to clear the moisture.
NOLAG
10-15-2011, 11:15 PM
thankyou guys for clearing that up me .. much appreciated!