140 IAC Count from Scanmaster??
Thread Starter
Registered User
Joined: Sep 2002
Posts: 200
From: Woodbridge, Va
140 IAC Count from Scanmaster??
I was checking everything out today, and I noticed that my scanmaster was giving me reading of 140-143 for the IAC at idle. The cam is a CC306 and it idles "well" through a BBK 58mm TB. Is this a glitch in the Scanmaster as it should read 40-ish, or should I be looking for something? I was under the impression that the IAC topped out at 40. Anyway, does anyone else's Scanmaster give them faulty readings? Thanks.
Thread Starter
Registered User
Joined: Sep 2002
Posts: 200
From: Woodbridge, Va
I "think" it's OK. I've never been in a cammed car before and the CC306 is a little lopey. It's never given me any reason for concern before, but then again I just may not have known better.
Also, if I'm reading 140 which is high, why would I want to open my blades more? I thought 140 would be the equivalent of WOT. Thanks.
Also, if I'm reading 140 which is high, why would I want to open my blades more? I thought 140 would be the equivalent of WOT. Thanks.
Administrator
Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
The IAC motor keeps opening in steps until the idle speed comes up to where it is supposed to be. When it opens, it lets in more air through the IAC passage. If you start opening up the throttle blades, some air comes in thru the blades, and less has to come in through the IAC passage, so the PCM closes down the IAC motor. If you keep opening the blades, it will eventually go down to where ever you want it (20-40). Hopefully you have programmed to compensate for MAP being higher than the stock cam, to avoid surging at idle.
The IAC count is an 8-bit field, so in theory it could go as high as 255.
The IAC count is an 8-bit field, so in theory it could go as high as 255.
Registered User
Joined: Mar 2000
Posts: 180
From: Fort St.John, British Columbia, Canada
I am no expert, but on my OBDI setup, the IAC seems to peg at 160.
I had to open my blades a tiny bit to bring mine down under 100. But I plan on doing the BBK modification so the idle air goes into the intake, and not at the throttle blades. I hope this may help a bit.
I had to open my blades a tiny bit to bring mine down under 100. But I plan on doing the BBK modification so the idle air goes into the intake, and not at the throttle blades. I hope this may help a bit.
Registered User
Joined: Mar 2000
Posts: 180
From: Fort St.John, British Columbia, Canada
I am no expert, but on my OBDI setup, the IAC seems to peg at 160.
I had to open my blades a tiny bit to bring mine down under 100. But I plan on doing the BBK modification so the idle air goes into the intake, and not at the throttle blades. I hope this may help a bit.
I had to open my blades a tiny bit to bring mine down under 100. But I plan on doing the BBK modification so the idle air goes into the intake, and not at the throttle blades. I hope this may help a bit.
Registered User
Joined: Mar 2000
Posts: 180
From: Fort St.John, British Columbia, Canada
Registered User
Joined: Mar 2000
Posts: 180
From: Fort St.John, British Columbia, Canada
Thread
Thread Starter
Forum
Replies
Last Post
Nayr
LT1 Based Engine Tech
7
Mar 3, 2023 08:34 PM