IAC adjestment
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Joined: Sep 2001
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From: vancouver B.C
IAC adjestment
short story : can i start the car with the ADSL terminals connected (A and B) when setting the IAC as implied in the directions in the tech article quoted below
Long story: I went out to reset my IAC and TPS, but i couldnt entirley figure it out. according to the instructions in the tech article, i need to start the car WITH the jump wire still in the ADSL ( A and B terminals), but i think i've read someplace that it hurts the ECM if you start the car with the terminals connected. I've quoted the article below.
Another question- when i disconnected the IAC connectors and tried adjusting the idle air screw, i couldnt get the rpms lower the 500 because when i got close to it the car just stumbled and stalled.
i've ruled out vaccum leaks since i've checked (and repaired) them about a week ago
The article:
Long story: I went out to reset my IAC and TPS, but i couldnt entirley figure it out. according to the instructions in the tech article, i need to start the car WITH the jump wire still in the ADSL ( A and B terminals), but i think i've read someplace that it hurts the ECM if you start the car with the terminals connected. I've quoted the article below.
Another question- when i disconnected the IAC connectors and tried adjusting the idle air screw, i couldnt get the rpms lower the 500 because when i got close to it the car just stumbled and stalled.
i've ruled out vaccum leaks since i've checked (and repaired) them about a week ago
The article:
Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.
Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.
Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.
Re-connect the connector onto the IAC. Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).
If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.
Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.
Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.
Re-connect the connector onto the IAC. Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).
If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.
Thread Starter
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Joined: Sep 2001
Posts: 236
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From: vancouver B.C
just something else i noticed.... when i connect terminals A and B on the ASDL there's a noise resembling .... well sorta clicks... continuously coming from the IAC unless i unplug it
it never used to happen before
it never used to happen before
Supreme Member
Joined: May 2002
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The clicking from the ALDL is normal, when you jump pins A&B it energizes all the circuts, the IAC is extending, and keeps trying to extend more until you pull the jumper off or the connector.
Some say it is ok to start the engine with it jumped and others say no. Really there is no reason to have to start it jumped.
Put the jumper on pins A&B, wait a few seconds for the IAC to fully extend, remove the IAC connector, get in the car, remove the jumper and start the car, set minimum air, shut down, reconnect the IAC and set the TPS to .54vdc
Some say it is ok to start the engine with it jumped and others say no. Really there is no reason to have to start it jumped.
Put the jumper on pins A&B, wait a few seconds for the IAC to fully extend, remove the IAC connector, get in the car, remove the jumper and start the car, set minimum air, shut down, reconnect the IAC and set the TPS to .54vdc
Supreme Member
Joined: Jul 2001
Posts: 2,760
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From: Cove, Arkansas
Car: 85 Camaro SC
Engine: V6
Transmission: 700r4
Do not jump the aldl if you have the IAC out. I saw that happen at the shop I used to restore my car. The IAC pin or whatever its called is going to shoot out of it. LOL they never found it after it shot strait out the door and into a grass lot.
Last edited by 85SportCoupeto89RS; Jan 18, 2003 at 10:44 PM.
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