Accelerator Cable Problem
Advanced
Joined: Oct 2010
Posts: 80
Likes: 2
From: near Nuremberg Bavaria
The Primary Throttle Lever usually has more than one mounting hole for the stud the cable attaches to. The inner/lower hole is the correct one. Using the outer one gives the symptoms you describe. Other things could be wrong, but check this one first - it's easy.
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,328
From: At my Bar drinking and wrenching in Lafayette Colorado
Inadequate throttle lever travel is common to almost all C3 Vettes. Here is my write-up on the subject, taken from my Q-Jet Setup Paper (available from me via e-mail request):
Technical Explanation: Help! My Secondaries Don’t Work!
3. A more common and subtle problem is the issue of inadequate throttle cable travel. This is very common on Corvettes and Camaros. With a helper in the car and with the engine “off,” have the helper fully depress the gas pedal (with the engine hot and the choke wide open to assure that the lockout lever is disengaged). Observe the carb on the driver’s side and see if the secondary throttle moves to the wide open position: You can grab the throttle lever once the assistant has the pedal to the floor and see if you can move it further. If the gas pedal does not fully open the secondary throttle, you have one of several methods to fix this:
a. Remove your floor mat. I call this the “25 horsepower floor mat tuning trick.”
b. Install the throttle cable in the correct position on the throttle lever. The Q-Jet has an “upper” and a “lower” cable attach hole: The upper hole was used for trucks and station wagons. The lower hole was used for Corvettes, Camaros and Novas. If you install a Corvette throttle cable in the upper hole, you will never achieve wide open throttle since there is not enough cable travel to open the throttle from the top lever location.
c. Straighten your throttle cable attach bracket. The bracket that supports the cable at the carb is often bent slightly forward. If the bracket is bent or moved forward, it will not allow enough cable travel to open the throttle fully. Simply bend the bracket back just a tad: I use a big hammer and a steel rod to give it a whack. I call this the “25 horsepower hammer tuning trick.”
d. Fix your gas pedal linkage. Very often, the actual steel linkage coming off your gas pedal will be bent a little “flat.” This will cause the pedal to hit the floor before the carb is wide open. You can give the pedal more travel by simply grabbing the gas pedal and bending it up off the floor. Care should be taken not to damage any plastic pedal rod bushings when doing this: Support the plastic pivot points when bending the pedal rod so the plastic bushings do not break.
e. Fix the slop in the gas pedal attach lever. Many C3 Corvettes have a bit of wear on the lever that attaches to the gas pedal rod: The rod is "D" shaped, and the attach lever has a "D" hole with a screw tightening feature. If this "D" hole is worn, you can remove the lever, grind some material off the locking feature surfaces so it snugs up tighter, and re-install it to gain some travel
Technical Explanation: Help! My Secondaries Don’t Work!
3. A more common and subtle problem is the issue of inadequate throttle cable travel. This is very common on Corvettes and Camaros. With a helper in the car and with the engine “off,” have the helper fully depress the gas pedal (with the engine hot and the choke wide open to assure that the lockout lever is disengaged). Observe the carb on the driver’s side and see if the secondary throttle moves to the wide open position: You can grab the throttle lever once the assistant has the pedal to the floor and see if you can move it further. If the gas pedal does not fully open the secondary throttle, you have one of several methods to fix this:
a. Remove your floor mat. I call this the “25 horsepower floor mat tuning trick.”
b. Install the throttle cable in the correct position on the throttle lever. The Q-Jet has an “upper” and a “lower” cable attach hole: The upper hole was used for trucks and station wagons. The lower hole was used for Corvettes, Camaros and Novas. If you install a Corvette throttle cable in the upper hole, you will never achieve wide open throttle since there is not enough cable travel to open the throttle from the top lever location.
c. Straighten your throttle cable attach bracket. The bracket that supports the cable at the carb is often bent slightly forward. If the bracket is bent or moved forward, it will not allow enough cable travel to open the throttle fully. Simply bend the bracket back just a tad: I use a big hammer and a steel rod to give it a whack. I call this the “25 horsepower hammer tuning trick.”
d. Fix your gas pedal linkage. Very often, the actual steel linkage coming off your gas pedal will be bent a little “flat.” This will cause the pedal to hit the floor before the carb is wide open. You can give the pedal more travel by simply grabbing the gas pedal and bending it up off the floor. Care should be taken not to damage any plastic pedal rod bushings when doing this: Support the plastic pivot points when bending the pedal rod so the plastic bushings do not break.
e. Fix the slop in the gas pedal attach lever. Many C3 Corvettes have a bit of wear on the lever that attaches to the gas pedal rod: The rod is "D" shaped, and the attach lever has a "D" hole with a screw tightening feature. If this "D" hole is worn, you can remove the lever, grind some material off the locking feature surfaces so it snugs up tighter, and re-install it to gain some travel
