85 camaro z28
Stock 305
Nci remand ccquadrajet
I am having a problem with my idle. I set the idle to about 750rpm, has no problem sitting there the problem is when I tap the gas the idle goes up to 1000rpm and if I tap it again it goes up and hangs there. When I stab the gas the idle will drop to 900 rpm. I can manually press the throttle on the carb down an get it back to 750. I replaced my old throttle return spring and it did nothing for the problem but I can't seem to wrap my head around the problem. It's really annoying having to stab the gas to drop the idle an at the same time it's dangerous that it sticks. I took the base plate off an everything seems in order, put it back on the carb an seems to function properly it's just when it's hooked up the throttle doesn't want to return all the way. Any ideas will be greatly appreciated.

 

Is this when the car is cold? Cause the choke will keep it revved when cold.

 

No. The car is completely warmed up choke fully open and hot idle cam disengaged.

 

Ensure that the choke is fully open and that the secondary lockout is not holding the throttle off of the curb idle set screw.

Next check the throttle bores for wear by checking for play on the primary shaft WITH the throttle slightly open. Any wiggling can cause the throttle to bind.

 

I checked the throttle an its working fine. I also checked the secondary lockout and its not holding the throttle open. I noticed that it does not experience the problem untill its warmed up. i checked my o2 sensor at idle and it variates in the .08 range up an down some. I was thinking that it might be something after it enters closed loop. I went from a tbi on my last camaro to the ccquadrajet so excuse me if i sound a little uneducated. But what i was getting at is that could the ecm be advancing the time causing a higher idle or something to do with the amount of fuel...I dont quite know how the sensors work with eachother inline with the ecm and carb but im already leagues away from where i was at a few months back.

 

I was talking to a friend I work with he told me it could possibly be the accelerator pump not returning the throttle into place which might cause the sticking idle an would explain why stabbing the throttle returned it to where it's set. If anyone wants to chime in I'm all ears.

 

Try unplugging the throttle bump solenoid. A bad TPS can cause it to stay set at idle sometimes.

 

Your throttle return spring should do that, not the actual accel pump. Unless you mean the accel pump is sticking down when you let off the throttle.