Throttle Linkage - something is wrong.
Thread Starter
Melting Slicks
Joined: Aug 2005
Posts: 2,821
Likes: 204
From: Lincoln CA
Throttle Linkage - something is wrong.
I bought my 69 about a year ago. The previous owner had some minor work done on the engine and said that he noticed that the car didn't seem to have the same "pick-up" that it had before the repairs. I found that the car had the wrong throttle cable bracket and replaced it with the correct part. Still can't get enough travel in the cable to open the secondaries fully, which could explain the lack of performance. The engine is very healthy, posting over 190 lbs of compression on all eight cylinders when I bought it. I've had a Corvette "specialist" and my own mechanic have a look at it and they don't have an answer. Just can't get the cable to pull the carb linkage far enough to open the secondaries. Any suggestions?
Racer
Joined: Jul 2004
Posts: 414
Likes: 1
I had a similar problem with mine... couldn't get the secondaries on my Barry Grant to open completely. I tried several throttle brackets, I tried puting a spacer under the stock gas pedal mounting point, and an adjustable cable.
Finally I bought a Lokar cable, bracket, and pedal assembly. Worked perfect! The pedal is fully adjustable and the cable and bracket have adjustability. To install the pedal assembly, I used one of the stock mounting holes and drilled one new one. Also, I had to drill a hole about 1" below the existing hole where the cable passes through the firewall. I just plugged the old holes with plastic plugs.
Finally I bought a Lokar cable, bracket, and pedal assembly. Worked perfect! The pedal is fully adjustable and the cable and bracket have adjustability. To install the pedal assembly, I used one of the stock mounting holes and drilled one new one. Also, I had to drill a hole about 1" below the existing hole where the cable passes through the firewall. I just plugged the old holes with plastic plugs.
Thread Starter
Melting Slicks
Joined: Aug 2005
Posts: 2,821
Likes: 204
From: Lincoln CA
One of my objectives is to keep this unmolested 70K mile car as correct as possible. My theory is that, with the original type Q-Jet and the original type cable and bracket, there must be something that is preventing it from traveling fully. I can't attest to the carb and cable being the actual cables that the car came from St. Louis with, but they very well might be. If it worked in the day, there must be an adjustment that I'm not understanding. I have the cable clamped in the bracket all the way up to the flange, providing maximum distance between the throttle linkage and the bracket. Everything else looks like it's not adjustable. I'm sure the secondaries aren't opening fully.
Pro
Joined: Aug 2005
Posts: 704
Likes: 2
From: Cincinnati OH
if it's of any help check out the pictures of my quadrajet and the troubleshooting we did. I finally got them working by moving the main throttle cable linkage.
http://forums.corvetteforum.com/show....php?t=1471214
http://forums.corvetteforum.com/show....php?t=1471214
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
http://forums.corvetteforum.com/show....php?t=1471214 Mongoose dont know what happen to yours but here it is again
Drifting
Joined: Dec 2004
Posts: 1,345
Likes: 3
The other thing that can cause this is that your gas pedal lever might be bent. Any bend near the cable reduces your available throttle travel. It is a single sheet of sheet metal where the cable goes through and is easily bent. I brazed a reinforcement on mine so it wouldn't EVER bend again!!
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Safety Car
Joined: Oct 2004
Posts: 3,923
Likes: 733
From: Youngstown Ohio
Originally Posted by StickShiftCorvette
The other thing that can cause this is that your gas pedal lever might be bent. Any bend near the cable reduces your available throttle travel. It is a single sheet of sheet metal where the cable goes through and is easily bent. I brazed a reinforcement on mine so it wouldn't EVER bend again!!
....had to do the same with mine.
Tech Contributor
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by RagTop69
Just can't get the cable to pull the carb linkage far enough to open the secondaries. Any suggestions?
Last edited by lars; Nov 13, 2006 at 10:47 AM.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Originally Posted by lars
I run into this issue on the Tuning Tours all the time. First, check the little lever that's screwed to your gas pedal with the "D" shaped hole - make sure it's not loose. If it's tight, simply grab the gas pedal as hard as you can and pull it up off the floor to bend the pedal lever - it takes a good, forcefull grunt to bend it. This will give you the travel you need.
Tech Contributor
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
You don't put any force on the plastic part when you grab the pedal rod and bend it up - you're only bending the steel rod that the pedal attaches to. Don't grab the pedal itself, but pull from the steel rod behind the pedal. I've "tuned" about 50 Vettes by bending the pedal like this, and nothing has broken yet...
Racer
Joined: Oct 2006
Posts: 306
Likes: 1
From: Burnaby BC
Thanks, my problem is that the previous owner did such a number on the lever that it old one does not have the wrap around and I can't remove the old weld to replace it with a new lever. Thus, it is really is not worth fixing anymore so I bought a one piece on ebay last night and hope that it fits the same way. I hope that the old plastic pivot and the new style I just bought have the same hole location to mount. If I could cut and past the pictures I would show you what I mean, but that is for me to figure out another day.
Last edited by tristan69; Nov 13, 2006 at 02:19 PM.
