Fast idle

[dcarey6]

2003/S2000

I have had my s2000 for a few months. I removed and re-installed the battery, removed and cleaned the throttle body and changed the coolant, etc..

I noticed that the engine idles at 2200 and I am not sure when this started.

The service manual says to turn on ignition for 20 seconds to reset ECM - did that.

The manual indicates that the cooling system must be bled, I am still getting some bubbles, could this cause less heat to the idle air valve and a high idle?

The manual indicates that if battery removed the ECM must re-learn the idle by bringing engine to temp and them running for 5 minutes at idle, did that.

Done all of the above, idle still at 2200 rpm. Any ideas?

[repiv]

Did it start on its own or did it start after you did some of things you listed? I'm just wondering if you did those things as a result of the high idle or if it went to high idle after you did those things. It is possible that the air passageways in the throttle body were in need of cleaning but the cleaning may not have been thorough enough in that you may have used the wrong product to do the cleaning and you didn't ensure that all the product and debris was blown out completely.
If you changed the coolant, then it's possible that you didn't bleed the system completely and there is an air pocket in the Idle Air Control mechanism. This can also occur when you removed the throttle body as there are coolant lines that were disconnected. Bleeding the cooling system requires the temp control knob to be set on HOT and the 2 bleed outlets opened in sequence while keeping the rad full. Did you do anything to the thermostat?

You may have misinterpreted the manual. Turning the ignition on will prime certain systems but it won't reset the ECU. Removing the battery (disconnecting power) did this already. I've never had any issues with the idle after disconnecting power.

I would concentrate on the cooling system bleed and the hoses going in and out of the throttle body. This is a continuous circuit that runs through the IAC lines.

Additionally, when you worked on the throttle body, did you confirm that the play in the throttle cable is to spec. If somehow that cable got pulled too tight, this will create havoc with the ECU and hence, the idle. Does your secondary air pump still come on during the initial stages after a cold start?