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IAC Hex Nut Size

cash's90

Well-known member
Joined
Jul 10, 2002
Messages
53
Location
Yucaipa, CA
Corvette
1990 Charcoal Metallic Coupe
My next project is to remove, inspect and clean my IAC. Idle is not too bad but I've read herein that the IAC is prone to crudding up. Based on my other findings, it's probably cridded up.
I plan to buy a deep socket suitable for the removal (my largest is 1 1/8") and I think it requires a 1 1/4" hex. Am I correct or is it a metric size (32 or 33 mm)?
Cheers,
Gary
:confused
 

fixvet

Well-known member
Joined
Apr 4, 2002
Messages
139
Location
Clever, MO
Corvette
1998 Two Tone Torch Red& Black Coupe
I'd like to know also!!
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
32 mm

With a little slop

But you cannot get a socket on it due to the clearance of the casting.

Options,

1) You can grind the side of the socket to get the clearance needed.

2) Pull the TB assy..... I mean if your gonna clean it... clean ALL of it.

3) NOT FOR THE WEAK BLADDERS

a 3/4 inch wrench fits on the plastic of the connector.... IF YOUR CAREFUL you can back it out that way.. but you do run the risk of breaking the IAC... so DON'T blame me!


Vig!
 

cash's90

Well-known member
Joined
Jul 10, 2002
Messages
53
Location
Yucaipa, CA
Corvette
1990 Charcoal Metallic Coupe
Vigman,
I found a Chinese made 1/2" drive 32 mm hex socket (also bought a 1 1/4" which does not work) for $1.99 in a tool warehouse. It was the only one they had. Ground down the O.D. to clear the TB. Worked like a champ.
The IAC cavity was cruddy and the tip of the IAC was crusty as well. Cleaned both of them up and reassembled.
I'd also carefully marked and removed the TPS to allow better access to the IAC. I was suprised to find that my TPS ('90 vette) is not adjustable. Perfectly round clearance holes for the mounting screws.
Once reassembled, all's well and the idle (smooth) speed has increased about 100 rpm.
Cheers,
Gary
:beer
 

cash's90

Well-known member
Joined
Jul 10, 2002
Messages
53
Location
Yucaipa, CA
Corvette
1990 Charcoal Metallic Coupe
I forgot to mention the my 32mm socket has a inside depth of 1.00" and a ground down o.d. of 1.58" (grind o.d. down to about 1/4" from front of socket to clear TB).
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Poifect!

Knyuck-Knyuck-Knyuck!


Ah so


Vig!
 
S

Shadowing1985v

Guest
i took mine off recently, and i had alot of black crap in it

i don't think i got mine all the way tight though

i think i need to turn it another 30 degrees to make it straight up and down

even though on photo's i see if the IAC i see it on a slant

is your guy's on a angle a little bit?
 
S

Shadowing1985v

Guest
i used the plactic nut,,

it did alright withme,,, just make sure you have the right size so you dont' round off the edges,, its just plastic
 

cash's90

Well-known member
Joined
Jul 10, 2002
Messages
53
Location
Yucaipa, CA
Corvette
1990 Charcoal Metallic Coupe
Shadowing,
My IAC does not have a flat side parallel with the ground when fully seated.
Cheers,
Gary
 

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