Idle Air Control Valve

[77CVT]

Do you have to the the TB off to get this thing out?  I wanted to check to see if it was fouled up.

Thanks

[Vette Obsessed]

It is definitely easiest to check the IAC with the throttle body off the car.

Just undo the four 10mm bolts, disconnect the throttle cable (and cruise cable), and use a large shifter to remove the IAC.  From memory, it should be set at 28mm (from the tip of the pintle to the top of the mounting gasket when you reinstall it.  Also, don't force the IAC pintle when moving it - you don't want to break it.

BTW, if you haven't already done the throttle body bypass now would be a good time...

[77CVT]

I was looking at the bypass option.

I guess I just join the hose at the drivers side of the TB with the short hose coming out at the IAC?

[Vette Obsessed]

Almost.  Last time I did a TB bypass was over two years ago but I recall you toss out the small hose that goes from the bottom of the IAC to the intake manifold.  You then run a hose from what used to go into the side of the TB and run it to the coolant port at the front of the intake manifold.  Hope this helps.

Its worth doing if for no other reason than making jobs like checking the IAC easier.

[Stingraynut]

Hi 77CVT, I did the TB bypass a few months ago. Yep, throw away the short hose with right-angle bend below TB and replace with r/angle hose with longer straight. On my 88 this joined up to a T join behind the altenator. The T is to make sure coolant reaches the rear of the engine (somewhere) a known hot spot.

I took the short hose to supercheap and found the longer one there – sorry don’t have any part numbers.

Sadly I can feel no power improvement but it makes sense to keep the incoming air cool as possible.

What symptoms do you have re wanting to check the IAC ?

S’nut

[77CVT]

S'nut

Just one of those things that seemed easy to check!  ;39

The TB was a bit gungy so I cleaned it out along the IAC holes and it idles a bit better now.