Fast Idle Cam Issue / Kick Down / Step Down
Thread Starter
Heel & Toe
Joined: Nov 2007
Posts: 16
Likes: 1
Fast Idle Cam Issue / Kick Down / Step Down
I tried searching for some post with similar issue. Didn't find one, so I apologize if this is a repeat from somewhere.
I have a 72 numbers matching Big Block. Car cold starts fine, and runs strong. I have one minor issue that has been driving be bonkers. I cold start the car, it will fast idle normally. After a while if I blip the throttel, it will setp down to like 1000rpms. Then after fully warm, if I blip the throttel it will sometimes. . .not always step down to the 800rpm bottom part of the cam. If however, I really give the peddle a hard blip (more of a hard rev) then it will always drop to 800 rpm.
Now, if I go and drive the car, when I get to the first stop light. . .it's back to 1000 rpm. If I hard rev it, down to 800. Green light. . .give it the beans. . .next stop light. . .back to 1000rpm. Repeat.
I cannot seem to get it to stay at 800 rpm.
I think the divorced choke is calibrated correctly (I can check it again). What else could it be? What would allow the fast idle cam to backup to a colder setting? I don't think adjusting the fast idle tension screw did anything last time I checked? Can the vacuum pull of have anything to do with it?
Thoughts?
Thanks!
I have a 72 numbers matching Big Block. Car cold starts fine, and runs strong. I have one minor issue that has been driving be bonkers. I cold start the car, it will fast idle normally. After a while if I blip the throttel, it will setp down to like 1000rpms. Then after fully warm, if I blip the throttel it will sometimes. . .not always step down to the 800rpm bottom part of the cam. If however, I really give the peddle a hard blip (more of a hard rev) then it will always drop to 800 rpm.
Now, if I go and drive the car, when I get to the first stop light. . .it's back to 1000 rpm. If I hard rev it, down to 800. Green light. . .give it the beans. . .next stop light. . .back to 1000rpm. Repeat.
I cannot seem to get it to stay at 800 rpm.
I think the divorced choke is calibrated correctly (I can check it again). What else could it be? What would allow the fast idle cam to backup to a colder setting? I don't think adjusting the fast idle tension screw did anything last time I checked? Can the vacuum pull of have anything to do with it?
Thoughts?
Thanks!
Race Director
Joined: May 2006
Posts: 18,710
Likes: 2,574
When the engine returns to the 1000 rpm idle you will have to check if the choke is partially closed.
You can also check when it does that if you close the throttle by hand on the carburetor does it drop back down to 800.
You can also check when it does that if you close the throttle by hand on the carburetor does it drop back down to 800.
