Cleaning IAC & cover assembly-How?
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Pro
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From: Cleveland Ohio
Cleaning IAC & cover assembly-How?
OK, I've removed the TB and the IAC from it. With no new IAC available today I'm going to atempt to clean it and the passages in the cover assembly. I've got TB spray cleaner that I plan to use. The IAC is covered with carbon and so is the seat in the cover assembly. If the IAC was making a good seal I'd doubt it. Any thing I should know about the cleaning process before I start/ Wire brush in passages and maybe a soaked rag for the pintail, which by the way looks off center......Thanks, Frank
Team Owner
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From: Sacramento CA
Re: Cleaning IAC & cover assembly-How? (Frank C)
fill up a glass with degreaseer and dip the pintle and spring into it. Do not let the degreaser get INTO it, just the pintle and spring. brush it off, gently, and dry it with the pintle down.
I sprayed Castrol superclean through the passage, it cleaned it FAST
I sprayed Castrol superclean through the passage, it cleaned it FAST
Instructor
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Re: Cleaning IAC & cover assembly-How? (Frank C)
:yesnod: :yesnod:
Put some Loctite 242 on the threads before you reinsert it. See the other recent thread on this for procedure for resetting if needed. If you don't pull or push on the stem (you're not supposed to, it will strip the worm gear inside), you can reinstall withou adjust ment. If your not sure, Push it in slowly and carefully ( dont Pull) so the stem isn't crushed when you reseat the threads. If you haven't yanked on it, leave it alone and it will be fine.
Put some Loctite 242 on the threads before you reinsert it. See the other recent thread on this for procedure for resetting if needed. If you don't pull or push on the stem (you're not supposed to, it will strip the worm gear inside), you can reinstall withou adjust ment. If your not sure, Push it in slowly and carefully ( dont Pull) so the stem isn't crushed when you reseat the threads. If you haven't yanked on it, leave it alone and it will be fine.
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From: Cleveland Ohio
Re: Cleaning IAC & cover assembly-How? (LouisBarton)
Thanks Louis, It went pretty good and now runs much better. I didn't use Loctite on the threads when reinstalling and did go a 1/4 turn past the orginal stop. Everything seems to be OK though I'm wondering if I should have used some anti-sez on the threads? Frank
Melting Slicks
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From: Tyler TX
Re: Cleaning IAC & cover assembly-How? (LouisBarton)
I just finished trying to clean my IAC. I took the TB off, cleaned it and removed the IAC from teh TB and cleaned it too. It had alot of carbon on it, and even had a chuck of crud on the tip. I got it all cleaned off put back together and adjusted. As long as the connector is disconnected from the IAC, I can get it to idle at 550-600 RPM's just fine. But when I turn the car off, reconnect the IAC and restart the engine, the idle shoots back up to 1200-1400 RPM. I guess that proves that there is a problem with the IAC. Guess I'll have to get a new one and try again next weekend. I DID however do the TB bypass while I had the TB off. So next time I have to remove the TB to put on the new IAC, I won't have a problem with coolant.
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From: Cleveland Ohio
Re: Cleaning IAC & cover assembly-How? (91-Z07Coupe)
Let me research your situation. I remember reading something about idle rpm with plug on and off and starting with the plug off etc....Frank
Melting Slicks
Joined: Oct 1999
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From: Houston, Texas FEAR THE BONES
2023 C5 of the Year Finalist - Modified
Re: Cleaning IAC & cover assembly-How? (Frank C)
I posted the factory service manual procedures for resetting a LT1/LT4 IAC under the "Tech Tips" section. You must perform the reset procedure when you clean the original IAC.
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Thread Starter
Pro
Joined: Mar 1999
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From: Cleveland Ohio
Re: Cleaning IAC & cover assembly-How? (94vette)
91ZO7Coupe has a L98 in his 91 I believe. He also refers to the fact that he has adjusted the IAC "back together and adjusted". I assume he means the, start engine form a partial throttle open position, let run at that same open position for 5 seconds and shut down, count 10 seconds and restart with NO throttle. That should reset the IAC valve. I was referring to reading somewhere about starting without the connector attached and what it does or causes and how to reset that problem...Frank
Melting Slicks
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From: Tyler TX
Re: Cleaning IAC & cover assembly-How? (Frank C)
I followed the Tech Tip for adjusting idle speed on early C4's. Everything is fine when I'm following each step. It's only when I restart the car after re-attaching the IAC connector that the idle shoots back up.
