C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

iac replacement

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Old Aug 22, 2011 | 06:52 PM
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Default iac replacement

i need to change the iac in my 86 and was wondering how hard is it and do i need any special tools?
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Old Aug 22, 2011 | 07:57 PM
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1. Dont be surprised if the plastic wire terminal crumbles in your hand. You can get a new one at PepBoys.
2. Be sure the pintle is not extended when you install it.
3. You can adjust it when you install it or just drive the car around and let it adjust itself.
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Old Aug 22, 2011 | 08:49 PM
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1and1/8 in wrench
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Old Aug 22, 2011 | 09:36 PM
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its easy; follow instructions; pintle should only be extended a specific amount when installed.

take the opportunity to throughly clean all the passages and throttle blade assembly with brake or carbureator cleaner.

finally, if your hot water circuit through the throttle body has not been bypassed, consider it a good time to get a throttle body gasket set and renew all the gaskets (there's only a couple).
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Old Aug 22, 2011 | 11:10 PM
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Originally Posted by stevebrochu
i need to change the iac in my 86 and was wondering how hard is it and do i need any special tools?
I removed the throttle body when i replaced mine in my 86---4 bolts and you have too undo a couple of small coolant hoses...not hard at all.
Remove old IAC clean the hell out of the throttle body with carb cleaner and a tooth brush---spray cleaner into the air passages until all the black carbon has run out---install new IAC --set the pintle extrusion to 1 1/8" new gasket--bolt up the throttle body and your done
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Old Aug 23, 2011 | 01:23 PM
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If you have no mods you can probably get away with using the FSM method, I gather. I prefer to use my scanner and get it via the IAC counts.
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Old Aug 24, 2011 | 06:26 AM
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I just push the pintle all the way into the IAC and short ALDL terminals A & B. Turn on the key and it calibrates itself. Turn off key, remove ALDL short, start car normally.
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Old Aug 24, 2011 | 07:54 AM
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Originally Posted by Cliff Harris
I just push the pintle all the way into the IAC and short ALDL terminals A & B. Turn on the key and it calibrates itself. Turn off key, remove ALDL short, start car normally.
That isn't even fully the stock procedure to calibrate it. All that does from what I can see is retract the pintle and assume that the throttle blades are correct. YOu could do without the shorting of the terminals and I believe the result will be the same.
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Old Aug 25, 2011 | 01:55 PM
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thanks for the info everybody i will try it this weekend if we don't get hit with a hurricane here in nh
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Old Aug 25, 2011 | 02:44 PM
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This is why its important to have a "Factory Service Manual"for your car.. You have had at least 3 different methods for the IAC install decribed to you .. I will agree that removing the Throttle body is the best way to do it..This allows you to clean the entire TB and makes installing the IAC much easier......WW
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Old Aug 31, 2011 | 07:21 PM
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thanks guys i changed it yesterday it was a piece of cake. glad everybody told me to pull the tb it was full of carbon.
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Old Aug 31, 2011 | 10:42 PM
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Originally Posted by stevebrochu
thanks guys i changed it yesterday it was a piece of cake. glad everybody told me to pull the tb it was full of carbon.
What a surprise. Whoda thunk it In all seriousness, I found less crud when I removed the EGR and PCV altogether
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