so... where IS the iaa valve? i searched, i swear - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Nerfdude · 01-22-2003, 08:16 PM

hi, my name's adam, and i have idle irregularity issues.

i did a lot of searching, and although i have found a lot of info on iaa related problems, one big important piece of information remains unknown: where IS the IAA valve?! after reading the following, i want to try to establish another ground wire.

Quote:

I have a 1991 240SX. I had this idle irregularity problem and took the car to the dealer after I saved some enough money. After several hours of head-scratching, they figured out the IAA valve (which controls the air intake to the fuel injector) was the problem. All they did was to establish an extra grounding wire and also covered the original connecting cable with plastic tape to secure the proper grounding. Now I don't have to fix my eyes to the tachometer each time I press the clutch pedal. It was a really irritating experience and cost about $120, which I think worth it.

so, if someone could just tell me whre the damn thing is... please... i'd be eternally grateful. FSM scans would be even better, but that may be pushing it...

datkwikracer · 01-22-2003, 11:57 PM

The IAA valve assembly is located on the passenger side of the motor down
below and behind the intake manifold. It's about 8" from the firewall.
According to the Nissan shop manual, to adjust the IAA valve, disconnect
the throttle sensor harness connector with the motor shut off. Now with the
engine idling in neutral, adjust the IAA for an idle speed of 650 RPM. With
the motor shut off, reconnect the harness connector. Now with the motor
idling, you should have an idle speed of 700 RPM. If you can't get the
proper idle speed, the AAC valve may be defective as It's the one that
receives signals from the ECU. The AAC bolts on to the IAA.

Hope this helps.
got this from faq's at 240sx.org

Nerfdude · 01-23-2003, 01:46 PM

thanks... how do you GET to the IAA? it seems to be completely surrounded by the intake...

boosteds14 · 01-23-2003, 02:23 PM

im pretty sure you will need to remove the intake manifold. I found that the easiest on mine because i didnt feel like removing all the other bullshet around it

Nerfdude · 01-23-2003, 03:46 PM

that was my fear.... but that raises another question. if i have to disassemble my engine to get to the iaa, how the hell do i adjust the iaa while the engine is idling?

Nerfdude · 01-23-2003, 07:02 PM

i took off the intake pipe and hosed down the throttle body with carb cleaner, and also sprayed a liberal amount down the hose leading to the IAA. cleared up all idle problems. i've only driven it about 15 or 20 miles since then, but it's been driving fine.... so, anyone with idle irregularity: a can of carb cleaner can go a long way.

01-23-2003, 02:23 PM	#4
boosteds14 Zilvia.net Advertiser Join Date: Jan 2002 Location: CIPmotorsports Age: 43 Posts: 1,612 Trader Rating: (0) Feedback Score: 0 reviews	im pretty sure you will need to remove the intake manifold. I found that the easiest on mine because i didnt feel like removing all the other bullshet around it __________________ 240SXONE www.240SXMOTORING.com --- One Stop Shop for Your Nissan 240sx

01-22-2003, 11:57 PM	#2
datkwikracer Zilvia Member Join Date: Oct 2002 Location: 909/714 So Cal Age: 43 Posts: 164 Trader Rating: (0) Feedback Score: 0 reviews	The IAA valve assembly is located on the passenger side of the motor down below and behind the intake manifold. It's about 8" from the firewall. According to the Nissan shop manual, to adjust the IAA valve, disconnect the throttle sensor harness connector with the motor shut off. Now with the engine idling in neutral, adjust the IAA for an idle speed of 650 RPM. With the motor shut off, reconnect the harness connector. Now with the motor idling, you should have an idle speed of 700 RPM. If you can't get the proper idle speed, the AAC valve may be defective as It's the one that receives signals from the ECU. The AAC bolts on to the IAA. Hope this helps. got this from faq's at 240sx.org

01-23-2003, 01:46 PM	#3
Nerfdude BANNED Join Date: Jul 2002 Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	thanks... how do you GET to the IAA? it seems to be completely surrounded by the intake...

01-23-2003, 03:46 PM	#5
Nerfdude BANNED Join Date: Jul 2002 Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	that was my fear.... but that raises another question. if i have to disassemble my engine to get to the iaa, how the hell do i adjust the iaa while the engine is idling?

01-23-2003, 07:02 PM	#6
Nerfdude BANNED Join Date: Jul 2002 Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	i took off the intake pipe and hosed down the throttle body with carb cleaner, and also sprayed a liberal amount down the hose leading to the IAA. cleared up all idle problems. i've only driven it about 15 or 20 miles since then, but it's been driving fine.... so, anyone with idle irregularity: a can of carb cleaner can go a long way.