How to Replace IAC?

[DeepPower]

My '89 SHO has a rough and high idle on cold start, but if I knock on the IAC a few times before starting the car it's almost normal. So I want to replace the IAC.

Can anyone tell me if I have to remove the intake manifold to replace the idle air control valve, or is there a way to get to that lower bolt without removing the manifold?

Thanks!

 

[luigisho]

Yes you get a socket with the correct hex bit and a few long extensions and route it under the runners with the intake still attached. I think 1/4 drive extensions fit easier. Be careful with dropping the tiny fastener when it comes out. If you don't have them already harbor freight should have them cheap.

A few times I have taken the replacement IAC and cut the bottom of the bottom mounting hole into a slot to make removal easier the next time but I'm weird like that.

 

[Irish Pride]

If you find just the right Allen key you can get to it too. I think it's a 5mm iirc but I could be mistaken. The set I have in my tool kit works perfect to get it loose and then I use my fingers to twist it out the rest of the way.

 

[zoomlater]

I've been able to use a right angled allen key as well, loosen the top fastener first to give you some room to loosen the bottom fastener. I also put a rag below the lower fastener to prevent it falling down into the intake valley

 

[rubydist]

I have also done it with the angled allen wrench.

btw, the atx design of the iac is much easier to work around than the mtx design, and they are interchangeable as far as function.

 

[DeepPower]

Thanks for all the good information!

A few times I have taken the replacement IAC and cut the bottom of the bottom mounting hole into a slot to make removal easier the next time but I'm weird like that.

I especially like this technique.

A few manufacturers make the IAC. Any suggestions as to who makes the best quality, or all they all made by the same guy in China?

 

[rubydist]

no, the "budget" category ones are not as good of quality as the "standard" quality ones, and I have had "budget" ones stick right out of the box. spend a little more for the better one.

 

[zoomlater]

I've bought several from Shosource without issue

 

[DeepPower]

I've got a BWD IAC around somewhere. I kept tripping over it until now, that I need it, I can't find the thing.
Of course if I buy another one we all know the lost one will magically reappear...

 

[Devin]

I've bought several from Shosource without issue

Hopefully for different cars?

 

[DeepPower]

I've bought several from Shosource without issue

All for the same car?

 

[zoomlater]

All for the same car?

One for an ATX and two for an MTX

 

[DeepPower]

One for an ATX and two for an MTX

Why two for the MTX?

 

[zoomlater]

Why two for the MTX?

Multiple MTX SHO's

 

[itwonder]

Sometimes, you can fix the IAC by taking it apart and cleaning it. It has been a long while since I did it, so it must have worked
I used a long 1/4" drive extension to reach through the runners and get to the difficult bolt.