Thread: IACV/Air Regulators for Everyone

^My UK 10.1 motor had one with the spring in it, and it was made between the years of 93-97 I believe.

The spring one replaced the original design..
Nissans New & Improved IACV (IAA) was introduced as replacements starting 1994..

But, I have ordered a replacement from an aftermarket site (RockA--- ) and received one without the spring. I promptly returned it...
So be aware that the old type ones are still in circulation!!

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Vad,
Use the one with the spring in it..
It will require cleaning but will not clog up as often.

I found the best way to clean the flaky carbon from inside of the IACV (IAA) is as follows:

1. Remove IAA from the car (royal PITA especially if you have AC & Power Steering).
2. Test the AAC & FICD components with your DVM per FSM instructions.
3. With the bottom side facing up (on a flat surface), Fill all cavities to the top with
- Valvoline SynPower Throttle Body Cleaner. This stuff will dissolve all of the carbon and works best..
- DO NOT brush the carbon as this will only move carbon flakes around but not out the unit.
4. Spray the SynPower cleaner into the Intake mani IACV/IAA openings. Let soak & wipe clean.
- Retreat to remove any buildups..
5. Let this sit overnight and pour our all of the dirty liquid. Wipe clean. OR
- Quick method: Let the IAA soak for an hour, pour out; do this twice refilling with cleaner and then wipe clean.
6. Remove the Idle screw. Spray inside the screw opening and clean using a Q-tip. Clean the idle screw and reinstall.
7. Remove the AAC cylinder.. Be aware the AAC cylinder has a small spring inside.
- Make sure to catch the little spring during disassembly.
- Clean the AAC plunger with a little cleaner & make sure the plunger is not sticking. Reassemble.
8. I normally clean & test (following FSM instructions) the Air Regulator during this step using the same SynPower
- cleaner. Let soak for 30 minutes on Each side opening to clean the metal by-plate on each side.
- Clean the inside of the hoses too. Then reinstall.
9. Reinstall the IACV/IAA, put car in timing mode, & Reset your idle.
Done...

How on earth did my 99 get stuck with it... maybe it is an aftermarket after all

Nope.. Someone installed an old one in your 99..
Maybe a dealer with some old stock! lol..

The old style still works, just require more cleaning intervals.

what are some of your guys symptoms of a clogged aac valve or dirty aac valve?

Normally its a bouncy idle & bogging on takeoff.

Im out of town but I can take pics later. I have neither of the units pictured by DC Scotty. I use the screw with the nut that is on the tb to adjust the idle.

Thats different than the normal SR20 setups. Never seen one with the TB screw.. Yours is definitely different and will require other techniques.

Most of us have the Nissan screwy IACV multiple unit arrangement and my writeup is addressing ONLY that setup..

im pretty sure all of the throttle body comes with the idel air screw personally i use that nut and screw along with the aac valve to get a lower steady idle....if im not mistaken that nut and screw is what gives your engine the constant flow of air, the more the screw is screwed in the higher the idle, the lesser the lower. but the iacv and the aac valve use the consistant flow of air and remeter it to a certain rpm working along with your ecu and MAF thats how you get a steady consistant idle.

i wish that we could do away with the iacv and the aac and just have the throttle body idle screw that would be so much easier.

like on hondas the butterfly sits flush and closed and there are 2 holes that let the engine have a consistant flow of air and then use the iacv to remeter it to a certain rpm....

our butterflies dont sit flush otherwise there wouldnt be any flow of air and it would be choked off and die

Once my car has been running for few minutes it idles like a champ on just the tb screw. I was never able to get the AAC and IACV to work right.

I will say that you learn to simulate idle when the engine is cold; however it isn't as bad as you may think.