Idle Problems

[87forfree]

Hello all this is my first post here and i have a few questions.
I've tryed searching for an answer but can't find it first off i have an 87 carbbed a20 and whats hapening is that i have a miss at idle now when i put the car into gear the miss seems to get alot better if not go away completly.
I have a exhaust leak from my flex pipe but i noticed that when i put my hand over the large pipe that is in the air cleaner base the car smothes right out, what i was figureing was that because of the exhaust leak the hole wich i belive is part of the egr system is acting like a vacuum leak??. sorry about the novel hehe any help is very much apreciated

Thank you

[A20A1]

hmm the large pipe that sucks in air?

If that is the case then you probably have a vacuum leak...

[87forfree]

i guess that was a little vague :) when you take the top off the air cleaner there is two air bleeds to the left (looking from the front) then on the lower right there is a large round inlit? i belive it's part of the EGR but i'm not positive and i don't mean the carb inlet :lol:

['89AccordLX(Rus)]

That is an air suction pipe. It is part of the air injection system that basically injects fresh air into the exhaust stream at the exhaust manifold. The only vacuum operated device in that system is the air suction valve. If you look right behind your valve cover, you'll see a black plastic housing and a valve to the side of it. Disconnect and plug the vacuum hose going to the valve and see if it makes a difference. My valve was bad and allowed the exhaust gas to enter the air cleaner housing. Unplugging it disables the system. Hope this helped.

[A20A1]

I knew what you meant :D

What gets me is when in gear it gets better... so maybe it's just that the idle contorler is saving you. You have an auto right?

[A20A1]

That is an air suction pipe. It is part of the air injection system that basically injects fresh air into the exhaust stream at the exhaust manifold. The only vacuum operated device in that system is the air suction valve. If you look right behind your valve cover, you'll see a black plastic housing and a valve to the side of it. Disconnect and plug the vacuum hose going to the valve and see if it makes a difference. My valve was bad and allowed the exhaust gas to enter the air cleaner housing. Unplugging it disables the system. Hope this helped.

It injects air but the AS valve also applies vacuum to the white valves right.?. Vacuum is tied in to a few of them too via #16 EGR, #30, #31, and #32 CURISE and A/C, and a few other unlabled vacuum hoses that go to manifold vacuum.
I beleive the AS system doubles as a vacuum pump from idle to below 3,000-3,600 rpm to maintain a high or constant vacuum signal. Above 3,600 the air injection valve cuts off or when manifold vacuum has dropped enough... then I beleive venturi vacuum is strong enough to run anything that will require vacuum beyond that.