Iac count
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Joined: Aug 2016
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From: kent
Iac count
This may be a stupid question so don't shoot me down but can someone tell me what a iac count is and how I check this on my 86 c4..as I understand it it changes the idle speed or idle speed control?.....
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Joined: Aug 2004
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From: Park City Utah
0 means that the ECM has closed or is trying to close the valve that meters air for idle speed (the Idle Air Control valve). You would only see "0" if there was a large vacuum leak.
255 would be the position for the valve ALL the way open. I have never seen that. Typically on a warmed up engine w/no loads on it (A/C or alternator charging etc) IAC counts will be in the 10-15 region.
You can observe the IAC counts w/a scan tool.
255 would be the position for the valve ALL the way open. I have never seen that. Typically on a warmed up engine w/no loads on it (A/C or alternator charging etc) IAC counts will be in the 10-15 region.
You can observe the IAC counts w/a scan tool.
