Wood

Hey guys, I've got a problem I've been trying to diagnose with my 83' 88 with a bone stock CCC quadrajet 307 and all smog equipment.

The car develops a high idle when warm, and it does not come down. When the engine is cold the idle is right where it should be.

When the car is warming up (idling) the idle will kick up by itself after a few minutes. Hitting the throttle does not bring the idle down. When the idle jumps up the throttle linkage does not move at all, nor does the choke, or anything else I can see for that matter. The linkage is still sitting on the set screw when it does this. So I am assuming there might be something with the CCC system creating this problem.

As of right now I have no idea on where to start looking for problems, and I am getting completely lost in the csm I have. Figured I would throw this out here to see if anybody has any ideas or has had a similar occurance.

Any help would be greatly appreciated, thanks guys.

jcdynamic88

the idle speed increasing after running a few minutes is probably the computer going into closed loop and is advancing the timing which would raise the idle as it should,by this time the choke thermostat should be heating up and kicking the throttle should bring it off the hi idle cam.make sure the choke is opening all the way and the choke/idle linkage is dropping.does it have an electric choke? if not check the tube that goes from the choke housing to intake manifold and it should get hot,if not there is a vacuum port in the carb that gets plugged and it wont draw hot air past the choke spring.

BlackGold

I'm speculating here, as I've never diagnosed your exact problem. But I think the vacuum break on the back of the CCC Q-jet is able cause a high idle, and I think it's controlled by engine temperature (though I'm not sure if it's direct control or as commanded by the computer).

76olds

You could try pulling the vacuum line off the EGR valve and plugging it with your finger once it warms up see if it makes a difference.