'82 with a HIGH idle

[jiangtao]

I just bought an '82 and it has an unusually high idle. When I put it in park or neutral after driving it shoots up to 2500+ RPMs. I asked this same question on corvette forum,but I am posting here to see if can get some more info. Today I took the Crossfire intake housing off to look at the TBs. From what I can tell they have never been taken off and the car has 85k on it. A question I haven't asked before is that my tachometer is screwed up. When I shut the car off it will stick at about 3k RPMs. When I turn the ignition{not firing to start} it will drop. Could this have something to do with my problem?

 

[brusso]

Well, I think that you could tell if the tach was that far off. If it is idling at 2500 and you put it into gear, you'll know it. Just make sure there is nothing in front or behind when you do. I would guess that the tach is not accurate at low speeds.

 

[jiangtao]

The funny thing is that when I do put it into gear it automatically idles down. Thank God!!

 

[brusso]

The funny thing is that when I do put it into gear it automatically idles down. Thank God!!

Does it idle down to where it should be? Something like 600-700 rpm or so?

 

[zgator]

My 82 CE idles at 500 rpm I think thats a little low.

 

[brusso]

My 82 CE idles at 500 rpm I think thats a little low.

Probably not, I think the sticker on my 75 says 550 for a manual or auto in drive. I think I'm around 600 in drive and 700-750 in park. Can't say that I've recently taken the time to notice. I've been pretty lucky this season with things not breaking.

 

[geekinavette]

I would suspect either a leaking plenum lid or a stuck IAC valve. High idle is almost always a vacuum leak.

Bill

 

[jiangtao]

I was looking a little closer the other day and noticed that I don't have a TBI gasket on the driver's side TBI. Guess that would about sum it up!! I am going to go ahead and rebuild the TBs and do some other small things to it. Thanks.

 

[geekinavette]

No gasket at all? Yikes! That's kinda scary.

You'll want to make sure you balance the TBs also (a water manometer is the best way to do it...as long as the TBs haven't been overbored).

Bill