# SR IACV (AAC) (Not your average problem)

**URL:** <https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545>\
**Category:** SON240sx Automotive\
**Created:** [April 4, 2006, 7:02am UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545 "2006-04-04T07:02:32Z")\
**Posts on this page:** 10\
**Page:** 2

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**Author:** ![ziptied](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ziptied/32/5509_2.png) [@ziptied](https://forums.speedlife.net/u/ziptied)\
**Post date:** [April 6, 2006, 8:43am UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/21 "2006-04-06T08:43:30Z")

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I have the same problem on my kat right now but i was reading the safc manual and it talks about something called the “deceleration air upper limit setting”

Here’s what it says

In case of a turbo vehical equipped with a hot wire type airflow sensor, the engine may be stalled by blow-back when the throttle is released. In this case, engine stall can be pervented by using the deceleration air upper limit setting. With the deceleration air upper setting, an upper limit is given to the airflow output voltage at the engine rpm set at Ne01 and Ne02 (Ne01 and Ne01 of Ne-point) below the Thr throttle opening.

I haven’t got my problem fixed yet and if someone knows how to work the safc2 than any help is appreciate

thanks  
and i hope this helps you as well

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**Author:** ![DTS](https://avatars.discourse-cdn.com/v4/letter/d/8491ac/32.png) [@DTS](https://forums.speedlife.net/u/DTS)\
**Post date:** [April 6, 2006, 7:32pm UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/22 "2006-04-06T19:32:40Z")

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what is a BISS

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**Author:** ![jammin1911](https://avatars.discourse-cdn.com/v4/letter/j/a9a28c/32.png) [@jammin1911](https://forums.speedlife.net/u/jammin1911)\
**Post date:** [April 6, 2006, 8:02pm UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/23 "2006-04-06T20:02:25Z")

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Base Idle Speed Screw I believe

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**Author:** ![Happy240sx](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/happy240sx/32/5515_2.png) [@Happy240sx](https://forums.speedlife.net/u/Happy240sx)\
**Post date:** [September 12, 2006, 6:44pm UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/24 "2006-09-12T18:44:50Z")

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Sorry to bring this up from the dead but just checking to see if you ever solved this problem D?

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**Author:** ![Gonad](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/gonad/32/5481_2.png) [@Gonad](https://forums.speedlife.net/u/Gonad)\
**Post date:** [September 12, 2006, 7:34pm UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/25 "2006-09-12T19:34:09Z")

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> [@Happy240sx](#):
>
> Sorry to bring this up from the dead but just checking to see if you ever solved this problem D?

He ran 13.5 @ 10psi. I’m pretty sure it’s solved. 😉

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**Author:** ![Lith](https://avatars.discourse-cdn.com/v4/letter/l/fbc32d/32.png) [@Lith](https://forums.speedlife.net/u/Lith)\
**Post date:** [September 12, 2006, 7:47pm UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/26 "2006-09-12T19:47:28Z")

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so what was the problem then? How did he solve it?

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**Author:** ![spd-dmn](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/spd-dmn/32/5513_2.png) [@spd-dmn](https://forums.speedlife.net/u/spd-dmn)\
**Post date:** [September 12, 2006, 8:28pm UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/27 "2006-09-12T20:28:33Z")

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It ended up being the mafs being too close to the compressor wheel.

Apparently some reversion will occur and the mafs gets confused and sends funny signals to the ecu.

I am sure Dustin will better explain what I just said.

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**Author:** ![Happy240sx](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/happy240sx/32/5515_2.png) [@Happy240sx](https://forums.speedlife.net/u/Happy240sx)\
**Post date:** [September 13, 2006, 3:38am UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/28 "2006-09-13T03:38:19Z")

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Ah - good old turbulence

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**Author:** ![turbo\_240sx](https://avatars.discourse-cdn.com/v4/letter/t/3be4f8/32.png) [@turbo\_240sx](https://forums.speedlife.net/u/turbo_240sx)\
**Post date:** [October 7, 2006, 7:47am UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/29 "2006-10-07T07:47:50Z")

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wow this thread might have just made me the happiest man alive…ive been goin through the exact same problem with my ca18det…if moving my maf farther from the compressor wheel fixes my problem aswell someone is a genious. 😃

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**Author:** ![Mista\_Sparkoh](https://avatars.discourse-cdn.com/v4/letter/m/3bc359/32.png) [@Mista\_Sparkoh](https://forums.speedlife.net/u/Mista_Sparkoh)\
**Post date:** [October 12, 2006, 8:29am UTC](https://forums.speedlife.net/t/sr-iacv-aac-not-your-average-problem/94545/30 "2006-10-12T08:29:41Z")

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> [@Sasha (Turbo)](#):
>
> i know exactly what you’e going through and 99% of SR owners go through this. im not sure if there is a definite answer other than standalone but this has always helped me:
> 
> #1 try to listen to the IACV and see if it is clicking. with a screwdriver up to it you should be able to hear some clicking similar to an injector. the IACV does work at idle
> 
> #2 if your TPS is set wrong or your idle is not calibrated correctly the engine will always be out of idle mode and be confused as to what it is supposed to be doing, not realizing that its job at the moment is to hold a current idle, or upon engine deceleration to CATCH THE IDLE (i.e. the IACV should go to a very high duty rate and let a lot of air flow in and slowly bring the engine speed down to 850rpm)
> 
> So what would make the car think it is not supposed to be idling? well if your TPS is tuned incorrectly and it thinks it is at 3-4% open when it is fully closed for example. Or if your physical throttle plate IS open slightly at idle. This is very bad.

this is the problem I’ve been having. When my engine decelerates, the rpms don’t “catch” and drop very low, causing the engine to struggle to prevent it from stalling. Where is the IACV and the TPS?  
I want to fix this problem ASAP so I don’t have to blip the gas to prevent the rpms from dropping too low

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