Idle-stumble HELP! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

v8killer · 10-24-2001, 04:16 PM

Can anyone help me out? I know the list has talked the idle stumble to DEATH, but I don't have a manual, and I wanna check my IAA valve. Anyone tell me WHERE it is, and/or pics of it?

Thanks in advance-

kclem69 · 10-24-2001, 08:45 PM

The IAA unit is mounted on the back (closest to the firewall) of the Intake Manifold Collector.  On the driver side of the IAA unit there is a small cylinder held on by two screws and on the passenger side of the IAA unit is the Idle Speed Adjusting Screw.  The Adjusting Screw is a little hard to see.  Mine was behind a hose.  The manual reads:  1. Before adjusting idle speed check hoses for leaks, check EGR valve, check air filter, yadda yadda yadda.  2. Start the engine and warm it to normal operating temp.  3. Race the engine to 2,000 - 3,000 rpm a few times then allow it to return to idle speed.  4. Connect a Tachometer according to manufacturer's directions.  5. Check idle speed.  6. disconnect the throttle sensor harness connector (It's on the passengers side of the throttle chamber and about 3 or 4 inches toward the battery).  7. Adjust the idle speed by turnign the idle seed adjusting screw (passengers side of IAA unit if you forgot).  8. Stop the engine and reconnect the throttle sensor harness connector.  9. Road test for proper operation.  You might have to repeat these steps to get it right where you want it.  I had to do this myself tonight.

I hope I helped,

Kyle Clemmons
1990 Fastback

10-24-2001, 04:16 PM	#1
v8killer Zilvia Member Join Date: Oct 2001 Posts: 150 Trader Rating: (0) Feedback Score: 0 reviews	Can anyone help me out? I know the list has talked the idle stumble to DEATH, but I don't have a manual, and I wanna check my IAA valve. Anyone tell me WHERE it is, and/or pics of it? Thanks in advance-

10-24-2001, 08:45 PM	#2
kclem69 Join Date: Aug 2001 Posts: 32 Trader Rating: (0) Feedback Score: 0 reviews	The IAA unit is mounted on the back (closest to the firewall) of the Intake Manifold Collector.  On the driver side of the IAA unit there is a small cylinder held on by two screws and on the passenger side of the IAA unit is the Idle Speed Adjusting Screw.  The Adjusting Screw is a little hard to see.  Mine was behind a hose.  The manual reads:  1. Before adjusting idle speed check hoses for leaks, check EGR valve, check air filter, yadda yadda yadda.  2. Start the engine and warm it to normal operating temp.  3. Race the engine to 2,000 - 3,000 rpm a few times then allow it to return to idle speed.  4. Connect a Tachometer according to manufacturer's directions.  5. Check idle speed.  6. disconnect the throttle sensor harness connector (It's on the passengers side of the throttle chamber and about 3 or 4 inches toward the battery).  7. Adjust the idle speed by turnign the idle seed adjusting screw (passengers side of IAA unit if you forgot).  8. Stop the engine and reconnect the throttle sensor harness connector.  9. Road test for proper operation.  You might have to repeat these steps to get it right where you want it.  I had to do this myself tonight. I hope I helped, Kyle Clemmons 1990 Fastback