What controls the fast idle cam.

i can click it up to idle normal, but after a short drive it drops down and idles high.

Is it a lever out of the choke asm or something to do with the intermediate choke lever and pull off?

cheers

 

When you pick up on the counterweight for the fast idle cam, the
idle should be faster and when the counterweight is all the way down, the fast idle screw should not touch the cam. When you open the throttle slightly and close the choke blade, the counter
weight should rise with it.

 

Its an electric choke, but disconnected and mutilated. The choke AV was held open with a cable tie and the fast idle cam was held in "normal" by some dodgey plastic and silicon blob.

With all the crap removed i get it dropping into high idle, the choke AV sticks open but i can just open and close it [shouldn't be able to do that ?]

There doesn't seem to be any relationship between the fast idle cam and choke movement, so I guess i'll just import a new choke Assembly to get that working again which should also fix the fast idle?

HAd the car 18 months and just started to restore, apart from a huge bog when floored, which i think is a misaligned / busted secondary AV setting its been ok for a couple of weekend runs.

 

The choke thermostat has a tab that hooks the pivot that closes the butterfly and moves the fast idle cam up. If things have been taken apart, then it probably isn't going to work in any fashion until returned to proper configuration. You could rotate the thermostat so that it doesn't put any tension on the choke/cam, and that would work for warmed-up running, but would be much harder to start. The electric power needs to be connected for the choke to work at all, anyway.

Also, there is a vacuum device called the choke pull-off. With a properly operating choke, the butterfly snaps closed when you tap the throttle before starting when cold. When the engine starts, the butterfly needs to be opened up a little, which is what the pull-off does. This should also allow the fast idle cam to drop down just a bit, so that when the throttle is tapped again, the idle will drop down one notch.

One other function of the pull-off is to keep the AV from popping open when the secondary throttle blades first open. As manifold vacuum drops, the pull-off will release, allowing the AV to open with the increased flow. This is in conjunction with the AV tension spring adjustment - you need both, although it is possible to "tune" the pull-off so it releases at the proper rate, independant of the AV tension.

Here's an expanded view of the q-jet, in case you need to figure out what parts you're missing. http://www.carbs.net/Quads/E4MC.htm The pull-offs are items 55 and 320. Some carbs have one or the other, or both (mine has #55 only).

 

cheers, i'll see if i can rotate it and keep the idle normal untill the new bit turns up.

I'll have to order online, none of the local guys stock any carb parts for the cc quadrajet.

luckily it never gets cold here so haven't missed the choke.