VAM door flutter at idle ??

[fripp]

What can cause the VAM door to flutter a lot, when the idle is bad ?
When I touch the door with finger the idle become stable.
This is a new VAM.
Thanks

[chalkys_explorer]

Hi Yves,
As far as i know, and Fleming may well be the expert here, the VAM door opens due to Vacumn within the intake tract. If your idle is rough this will cause the door to swing back and forward. If you idle is smooth the opposite would be true.

The fact that the idle is stable whilst holding the door opens suggests to me that the problem lies somewhere else. Do you have any vacuum leaks?? Whats the state of tune of the motor, new ignition parts??

Just my thoughts.

Chris

[fripp]

Hi Yves,
As far as i know, and Fleming may well be the expert here, the VAM door opens due to Vacumn within the intake tract. If your idle is rough this will cause the door to swing back and forward. If you idle is smooth the opposite would be true.

The fact that the idle is stable whilst holding the door opens suggests to me that the problem lies somewhere else. Do you have any vacuum leaks?? Whats the state of tune of the motor, new ignition parts??

Just my thoughts.

Chris

All the ignition parts are new except the pickup coil.
My vacuum is not stable, beetween 12 and 16 psi.
I am pretty sure your right about the vacuum problem and I will concentrate my efforts to find it.

Thanks a lot
Yves

[85ttops]

just start capping things at the vac tree when it smoths out you found it, repair and go backwards if it acts up again while pluging stuff back in then theres more then one

i hate electrical but i am real good when it comes to vaccume

[Millertime2]

I too had a serious VAM flutter issue on my car after I installed a Spearco FMIC kit a while back. It drove me nuts too until I found it, the car would have trouble at idle(surge, dying) and forget about turning on the A/C at idle. So how did I fix it? Simple I got a widband LM-1 meter, and then I adjusted the VAM door spring which I needed to lean the A/F about 1/2 a point at idle, and she idles pretty sweet right now. No other changes ocurred with the A/F at any other RPM or load so it's safe. If you do this make sure to use a dyno with a widband or use a in car version, you don't want to just start changing that spring without a way to tell what your doing.