First Generation Firebird
Posted By: Jago Accelerator pedal/cable - 04/15/17 04:04 AM
Hello, I'm having a lot of trouble with my pedal and would like to compare my setup with someone else. I have a 68 400 all stock and I would like to compare in particular someone's accelerator pedal connection to the throttle cable at the firewall. Mine seems to be off, the point of connection is higher than where the throttle cable comes through the firewall reducing some of my pedal travel. I am only able to obtain my idle speed at about 500rpm in drive or full throttle but not both at the same time. At 500 rpm my throttle cable is extremely taut against the inside of the firewall and my pedal hits the ground before I can reach full throttle. on the other hand, adjusting my setup to reach full throttle...I can't achieve 500rpms in drive. I can only get as low as about 900rpms. Also at full throttle in this scenario, the bottom of the accelerator pedal is a good 2 inches from the ground. Any help would be appreciated, I know it's hard to explain my problem. Any pictures of your stock 68 throttle setup would be great thanks!

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Posted By: Jimc2002 Re: Accelerator pedal/cable - 04/15/17 01:52 PM
This is original factory with the exception of the replaced blue spring and downshift switch boot and the additional non-factory backup safety (forward) spring:

Let me know if you want more or a different angle.



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Posted By: Firebob Re: Accelerator pedal/cable - 04/15/17 03:39 PM
What happens is after years of mashing the pedal it bends and you dont get full throw out of it anymore.
Posted By: Dr. Drivability Re: Accelerator pedal/cable - 04/15/17 04:15 PM
Agree with Bob, either the pedal assembly has been bent or there is a problem at the carburetor. The cable is a fixed length at fixed points at the pedal and the carb.
Posted By: cme469 Re: Accelerator pedal/cable - 04/15/17 06:52 PM
Jago, I once had a similar problem with mine and discovered the plastic mount where the peddle turns in the firewall had broken. Hard to get to, but once replaced the full travel returned.
Ron
Posted By: Bjorn Sefeldt Re: Accelerator pedal/cable - 04/15/17 07:01 PM
Reminds me of a HALF trip to Corpus Christi 4-5 years ago....after spening the weekend there we were getting ready to cruise back to Houston...I start my car up and pedal goes "snap"...cable broke...on a Sunday 200 miles away from home....thinking "Crap, its a special order from Ames or Classic"....but , as luck has it one of our hosts (Janine) says..."my husband just bought one for us to change out a week ago"....so she calls him, 10 minutes later its there ,and two of my buddies exchange out the broken one!! ..so 30 minutes after cable broke, were on the road....
Posted By: Jago Re: Accelerator pedal/cable - 04/16/17 05:42 AM
I have tried bending the pedal rod today with no luck, I still can't improve throttle range, I have also check the pedal assembly bracket at the firewall and it isn't damaged and secures tightly. I found that if I disconnect my throttle cable at the bracket by the carb and move the cable towards the front of the car a bit maybe 1/2" it allows me to achieve the correct throttle range. So that would mean something is wrong with my throttle bracket right? I'm not sure if my bracket is the correct bracket. If someone has a picture with dimensions of the correct bracket so I could compare that would be great.

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Posted By: HaroldB Re: Accelerator pedal/cable - 04/16/17 12:08 PM
The bracket looks correct and it has the part number stamped which I think is correct. Your throttle lever on the carb is wrong. I don't know if the measurements are different. If you looks at Ames Performace Catalog page 182 it shows different years. Yours look like a 70 year. Maybe they measure the same but they were diffent for each year.
Posted By: Jimc2002 Re: Accelerator pedal/cable - 04/16/17 03:20 PM
Comparing the pictures of the accelerator pedal rod of yours with mine, I believe a lot of your issue is the rod not aligning with the cable. By the time the slack gets taken up with that clip starting almost perpendicular with the cable, you have pushed a lot of pedal with little cable movement.

Also, there were two different throttle brackets in '68 depending on the intake manifold part number.
The 9790140 intake uses 9792242 bracket while the 9794234 intake uses an F4 bracket.
Posted By: Jimc2002 Re: Accelerator pedal/cable - 04/16/17 03:53 PM
Here's a picture of mine from the left (behind the steering column) showing the straight line between the cable entrance and rod. The accelerator pedal is at rest.so every bit of pedal depression will pull cable evenly.

Bjorn's post reminds me that I should order a spare cable, not knowing when this old one might fail. I keep a spare TH400 cable because I have had to replace mine twice through the years.



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Posted By: Jago Re: Accelerator pedal/cable - 04/17/17 08:31 AM
My intake is 9790140 so yes I believe my bracket is correct. I am unable to confirm if my throttle lever is correct, can anyone else tell? Here's a better picture of the throttle lever.

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Posted By: HaroldB Re: Accelerator pedal/cable - 04/17/17 09:52 AM
Here is a 68

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Posted By: Jimc2002 Re: Accelerator pedal/cable - 04/17/17 01:01 PM
It is incorrect. Compare to this top view of an original. Note the cable connecting much further to the left, perpendicular to the spring. There is no bend in the cable.

Posted By: Jago Re: Accelerator pedal/cable - 04/18/17 01:25 AM
Thanks I'm going to get the correct throttle lever and go from there.
Posted By: Jago Re: Accelerator pedal/cable - 04/21/17 05:51 PM
Yup the new throttle lever fixed my issue. Although, with the pedal floored I still have about 1/8" more play in the throttle lever until the throttle lever makes contact with the carb base plate. Is that good enough to get full throttle? I could easily bend the pedal rod to make the throttle lever actually make contact with the carb base plate if it's necessary.
Posted By: Dr. Drivability Re: Accelerator pedal/cable - 04/21/17 07:45 PM
Look down the throat of the Qjet and see where your secondary throttle blades are sitting. If they are at 90 degrees with the pedal floored, you're good. If not, modification to the carb linkage can be done to achieve it. It's in Cliff Ruggles book.
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