IAC count at zero
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
Team Owner
Joined: Jul 2004
Posts: 28,465
Likes: 3,288
From: Hartford WI
There may be the FSM method but I don't like it much. For my L98, get it to final operating tem then I shut everything but the motor off. Read the IAC counts. If it is 0, it tells me the motor is getting too much air. I'd back the screw off by turning it counter clockwise, rev and see if the counts go up. In your case, I keep turning it out about a half turn at a time. Each time you turn it, rev and let it settle down. Target is 20-30 IAC counts.
Intermediate
Joined: Oct 2007
Posts: 41
Likes: 13
The idle speed does not "increase 100 RPM" with the A/C on. The counts increase to keep the idle speed the same with the additional load of the Compressor.
There is a similar sub-routine for coolant fan control. The ECM increases IAC counts just prior to engaging the coolant fan to minimize the idle droop from the increased load on the alternator when the fan load comes on.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
There is a routine to increase the idle when the A/C is turned on to compensate for the compressor load. I have never seen anything related to coolant fans. I am looking at my '86 BUA code, so maybe there is something in the code for later years.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
The code specifies 100 RPM. It lets the ECM figure out how to get there, and the only way is to open the IAC.
There is a routine to increase the idle when the A/C is turned on to compensate for the compressor load. I have never seen anything related to coolant fans. I am looking at my '86 BUA code, so maybe there is something in the code for later years.
There is a routine to increase the idle when the A/C is turned on to compensate for the compressor load. I have never seen anything related to coolant fans. I am looking at my '86 BUA code, so maybe there is something in the code for later years.
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