Idle Problems, Maybe your IAC is bad.
Le Mans Master
Joined: Jul 2000
Posts: 7,633
Likes: 324
From: Greenville SC
I cleaned my MAF, TB, and IAC and it worked like a charm.
NO more dropped idle when I stop, now it stays high for a few seconds then drops down like before. Also I can run the AC when stopped and it maintains the idle. Side benefit is that I hardly have any rattling from my SM flywheel at idle now. Also it just seems crisper response, drives smoother especially at low speeds, no more bogging at take off. thanks!
NO more dropped idle when I stop, now it stays high for a few seconds then drops down like before. Also I can run the AC when stopped and it maintains the idle. Side benefit is that I hardly have any rattling from my SM flywheel at idle now. Also it just seems crisper response, drives smoother especially at low speeds, no more bogging at take off. thanks!
Pro
Joined: Jan 2004
Posts: 503
Likes: 0
From: Forney Texas
Thanks guys, I checked my IAC as suggested. What I first noticed was the connector seemed to come off of the IAC very easy. I did not have to fight with the locking tab nor did I have to pull with any force to remove it. I went ahead and removed the IAC and checked it with a multi-tester. Pins A and B ohmed 65 and C and D ohmed 66. Everything else looked good so I put it all back together and made sure the connector was fully engaged and locked this time. Started the car and it idled great, just like it has since the rebuild. 
I have concluded the only problem was the connector had somehow worked its way out of the IAC. Easy, cheap fix. However, I have learned something about the IAC so I guess it all worked out.
Thanks to all of you who posted ideas. My next hurtle is learning to datalog and tune.
90Indy
I have concluded the only problem was the connector had somehow worked its way out of the IAC. Easy, cheap fix. However, I have learned something about the IAC so I guess it all worked out.
Thanks to all of you who posted ideas. My next hurtle is learning to datalog and tune.
90Indy
Intermediate
Joined: Aug 2008
Posts: 36
Likes: 1
96 LT1
My new scanner arrived today and, guess what, it's telling me that the IAC isn't working either; no reading. On top of that, I'm not getting a MAF reading either.
All the other values are showing up real-time and there is no Check Engine code either stored or lit up.
I'll check the resistance of the IAC wiring to see 'what's up'; I just hope it's the same as your 93 because I can't find my Volume 2 FSM.
Jake
My new scanner arrived today and, guess what, it's telling me that the IAC isn't working either; no reading. On top of that, I'm not getting a MAF reading either.
All the other values are showing up real-time and there is no Check Engine code either stored or lit up.
I'll check the resistance of the IAC wiring to see 'what's up'; I just hope it's the same as your 93 because I can't find my Volume 2 FSM.
Jake
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,913
Likes: 37
From: South Carolina
St. Jude Donor '03 & '05
Melting Slicks
Joined: Mar 2008
Posts: 2,351
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From: Delta B.C. Canada
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I've been searching the threads regarding an idle problem that I'm told is IAC related. However, what I've got happening with my 92 LT1 does not appear in any posts I've looked at. After the engine has reached operating temp and I then re-start it, sometimes (maybe once out of every ten times) the idle will sit at around 1,800 RPM for as long as a couple of minutes. After that it drops back to 700 and everything else is fine. There are no other idle issues. I've done the resistance check and the IAC was in spec.
So, should I trying cleaning it first or just cough up the $80 for a new one and hope it fixes the problem?
So, should I trying cleaning it first or just cough up the $80 for a new one and hope it fixes the problem?
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,913
Likes: 37
From: South Carolina
St. Jude Donor '03 & '05
I've been searching the threads regarding an idle problem that I'm told is IAC related. However, what I've got happening with my 92 LT1 does not appear in any posts I've looked at. After the engine has reached operating temp and I then re-start it, sometimes (maybe once out of every ten times) the idle will sit at around 1,800 RPM for as long as a couple of minutes. After that it drops back to 700 and everything else is fine. There are no other idle issues. I've done the resistance check and the IAC was in spec.
So, should I trying cleaning it first or just cough up the $80 for a new one and hope it fixes the problem?
So, should I trying cleaning it first or just cough up the $80 for a new one and hope it fixes the problem?
And, go to www.partsamerica.com and look for the part there, and when you find it, printout the price and Checkers/Kragens or Shucks will honor the price. Not 80 bucks I believe its more like 40 something. ZIP code dependent.
Le Mans Master
Joined: Feb 2003
Posts: 9,087
Likes: 0
From: Chicago IL
I removed the IAC on my '94 , cleaned it and the pintle got broken when reinstalling it. Be careful when tightening the bolts because if it goes in slightly on an angle, this will happen. The o-ring was really dry and brittle and tore when I tightened the bolts causing an air leak.
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Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
The installation procedure in your FSM calls for retracting the pintle so it doesn't "get broken."
I removed the IAC on my '94 , cleaned it and the pintle got broken when reinstalling it. Be careful when tightening the bolts because if it goes in slightly on an angle, this will happen. The o-ring was really dry and brittle and tore when I tightened the bolts causing an air leak.
in every forum! they all, at 1 time or another, realize they are not well liked........
Melting Slicks
Joined: Mar 2008
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From: Delta B.C. Canada
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Yes clean it real good with sensor safe cleaners. Also, DO NOT push in the pintle, leave it as is as it can berak easily.
And, go to www.partsamerica.com and look for the part there, and when you find it, printout the price and Checkers/Kragens or Shucks will honor the price. Not 80 bucks I believe its more like 40 something. ZIP code dependent.
And, go to www.partsamerica.com and look for the part there, and when you find it, printout the price and Checkers/Kragens or Shucks will honor the price. Not 80 bucks I believe its more like 40 something. ZIP code dependent.
Would "electronics parts cleaner" qualify as a 'sensor-safe' cleaner? Would you soak the IAC or just spray and brush?
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 9,913
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From: South Carolina
St. Jude Donor '03 & '05
Melting Slicks
Joined: Mar 2008
Posts: 2,351
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From: Delta B.C. Canada
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On the LT1, is it necessary to remove the TB to get the IAC off? It appears that the bolts holding it on are underneath and it would be very tough to get any kind of wrench in there. I ask because in some other post it was mentioned that removing and reinstalling the IAC was a 20 minute job.
On another note, the FSM makes no mention of a MAF on the 92 LT1. Am I blind or does it actually not exist?
On another note, the FSM makes no mention of a MAF on the 92 LT1. Am I blind or does it actually not exist?
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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On the LT1, is it necessary to remove the TB to get the IAC off? It appears that the bolts holding it on are underneath and it would be very tough to get any kind of wrench in there. I ask because in some other post it was mentioned that removing and reinstalling the IAC was a 20 minute job.
On another note, the FSM makes no mention of a MAF on the 92 LT1. Am I blind or does it actually not exist?
On another note, the FSM makes no mention of a MAF on the 92 LT1. Am I blind or does it actually not exist?
Racer
Joined: Feb 2005
Posts: 374
Likes: 4
From: decatur ga
WHat I did was I took the leads from the fluke/multimeter and put them in the iac, where the plug goes in. A/B are the top two(the little tab that guides the plug correctly onto the IAC.) The wires are colored, so A/B will be blue w/white stripe and blue/with black stripe. C/D are light green/white stripe and light green/w black stripe. Look at how the plug goes into the IAC then look at the wires leading into the appropriate port.
Basically they should be in the range of 40-80 OHMS.
I cant find a pic of the IAC itself, but the tab you lift off to unplug it is ontop of AB, and CD are the bottom two you check. Remember, you are checking the resistance between A/B and C/D
Basically they should be in the range of 40-80 OHMS.
I cant find a pic of the IAC itself, but the tab you lift off to unplug it is ontop of AB, and CD are the bottom two you check. Remember, you are checking the resistance between A/B and C/D
and I got 49 from c to d does this make the IAC good