Quadrajet Throttle Spring
Thread Starter
Le Mans Master
Joined: Apr 2013
Posts: 5,001
Likes: 1,056
From: Arlington TX
2024 C1 of the Year Finalist - Unmodified
2023 Restomod of the Year Finalist
2023 C1 of the Year Finalist - Unmodified
Quadrajet Throttle Spring
It seems to me that it takes an exceptionally strong spring to get the primary throttle plates to close. If I use an ordinary spring, then I get a fast idle sometimes. Anybody else have trouble like this, or do I have something adjusted wrong?
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
If your front throttle blades bind, it could cause this. Binding can either be maladjusted plates or worn/bent throttle shafts.
A basic test I do is check to see if the throttle blades will shut completely with the throttle springs disconnected, cable disconnected and engine off. The accelerator pump return spring should be able to return the primary throttle blade to closed. If not, you've got a bind somewhere.
A basic test I do is check to see if the throttle blades will shut completely with the throttle springs disconnected, cable disconnected and engine off. The accelerator pump return spring should be able to return the primary throttle blade to closed. If not, you've got a bind somewhere.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You have binding somewhere. It could be in the carb, in the linkage, in the throttle cable, in the accelerator pedal or in any combination of them. Test the resistance of each without the others (if possible). Remove cable from carb and check linkage/mechanical resistance to full range of throttle movement. Then check resistance of cable movement, now that it is not connected to the carb. Get in the car and move accel pedal by hand.
Hope you find the problem.
P.S. It could be that the carb is not lined up 'true' with the gasket and intake manifold. This can be a source of binding (between throttle plates and gasket and/or intake inlet bores).
Hope you find the problem.
P.S. It could be that the carb is not lined up 'true' with the gasket and intake manifold. This can be a source of binding (between throttle plates and gasket and/or intake inlet bores).
