What Is Wrong With my Car?I get IAC Counts set and warm up it Goes to Hell!
#1
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Ok on my 408 with a 90 MM Fast Intake ,TPIS 90 MM TB,244 248@.05 cam,I get my Iac counts down to where I want them Get effective Area set ,Idle Air real close and the when car Idles for 20 minutes or so coolant temps are in the 190's The Damn thing will start Idling High for no reason ,My IAC Counts double and My Desired Airflow cuts in Half of what it was before.What Can Cause this?
Last edited by Pro Mouse; 12-05-2010 at 10:57 PM.
#3
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Are you measuring your IAC counts when fully warm with the AC off? They should be between 30-60 in neutral. When the motor is cold, they'll be anywhere from 150-200. If they're not, you have more work to do.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
![](https://ls1tech.com/forums/signaturepics/sigpic210_1.gif)
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#6
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When warm and at idle look at the Timing in °
When setting the IAC you need to cycle the key off (about 10 sec) and then restart the car and recheck the IAC counts.
I had a stock truck a few months ago that had an issue. Lets just say lack of power. The idle was fine untill you move the throttle and then the truck would start to die out, but it wouldn't the IAC counts were all over the place. The timing would jump to 48° and it would ping. This was at idle in park or in gear. Pinging at idle on a stock calibration. The idle speed was low and the PCM was giving it all the timing it could.
So you set the IAC, but the PCM changes the timing. That is why I recommend cycling the key
When setting the IAC you need to cycle the key off (about 10 sec) and then restart the car and recheck the IAC counts.
I had a stock truck a few months ago that had an issue. Lets just say lack of power. The idle was fine untill you move the throttle and then the truck would start to die out, but it wouldn't the IAC counts were all over the place. The timing would jump to 48° and it would ping. This was at idle in park or in gear. Pinging at idle on a stock calibration. The idle speed was low and the PCM was giving it all the timing it could.
So you set the IAC, but the PCM changes the timing. That is why I recommend cycling the key