[Diy_efi] Out of the blue high idle

[TomQ]

Thanks for the advice Joe! I tried the "plug small port in the top of the
throttle
body that feeds the IAC valve passage". That is it. The idle came way down
right away. I cleaned the snot out of the passage way but it still is open.
I then pulled the valve out a little so it plugs the hole. It did and the
idle was down around 600. I then kept revving the motor up and down and the
idle slowly crept up. I stopped at 1200 rpm. I am going to take a look at my
program to make sure the idle is correctly stated. Any way can take some
volt measurements to see if the valve is being "told" to open more then it
should?

-TomQ

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Joe Lutz
Sent: Thursday, July 03, 2003 12:44 PM
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] Out of the blue high idle


The answer to your question is yes.
If you unplug the connector, the IAC valve stays where it is.  So if it is
too far open, then it will still be that way when you unplug it.  Try just
unplugging the TPS and see if it idles down.  Check all your vacuum lines
and your brake booster for vacuum leaks.  You can just pinch off the line
going to the brake booster to see if that's the source of the leak.  Check
the pcv valve and line.  Check your throttle valves and linkage to make sure
the butterflies are closing all the way.
This may sound crazy but you can do this to see if the air is coming in
through the IAC valve.  There is a small port in the top of the throttle
body that feeds the IAC valve passage.  Use your finger to plug it to see if
it idles down or dies.  If it does, then the IAC valve is either letting too
much air in or not closing far enough to control idle speed.  Carbon can get
in the IAC passage and cause the valve to not seat all the way.  Use carb
cleaner to clean out the passage if that's the case.

Hope that helps,
Joe




_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi