I have a 1994 850 turbo. Trying to smog it in California but idle was to high @1200rpm. This was in park & drive!Needs to be 750 to 800 Rpm range.After testing IAC found that on the connector signal return side terminal 1 was reading .5 volts with ignition on which book says 6.0-8.5v. The pins on the IAC were in ohms range.I jumped the blue/white wire from the connector straight to ECU hoping it was a short in the wire run but same readings. Could it be the ECU? Any suggestions? Thanks to anybody that can help.

 

What happens when you un plug the IAC?

 

The idle definitely goes down to were I think it should be but ill hook up a better obdII scanner with live rpm readings to get a more accurate reading tomorrow. I'm going to test the TPS also. No check engine lights r on either.

 

Its most likely you IAC... Very rare that your ECU will do this...

You could try to see if you remove your throttle cable and close the tb all the way...

 

I know my turbo has an adjustable idle screw that you could possibly loosen to let the plate close a little more. You will see it right next to the throttle control on the throttle body. My TPS read .900 fully closed and around 2.6 ohm fully open. This was tested with the TPS off of the car so it probably wont read that high since the throttle wont open that much. Just to give you an idea of the range. Good luck my friend