302 Cable driven throttle transition from off to on throttle

[john42]

Finally was able to go to my first autocross this past Sunday, had lots of fun and certainly had my Cobra show me it was a far better car then my driving skill.

The one and only problem I had was being able to feather the throttle. The transition from "no gas" to just a "tiny bit" of gas was not possible. My throttle goes from zero to pretty hard at the first hint of touching the gas peddle. It only really bothered me before when I was trying to do a slow crawl out of a busy parking lot. However, during autocross I was either accelerating or decelerating and I was unable to maintain a pace that was just on the threshold of accelerating.

It's as if the pressure on the gas pedal to overcome the friction of the cable throttle is too high. So other then converting to mechanical linkage on a built car... what are some ways to look into improving the cable driven throttle?

[Papa]

Are you running a Holley Sniper or similar setup by chance? What you're describing is a pretty common complaint. The fix recommend in the Holley forum is to extend the throttle linkage about 1/2 inch to get a bit of angle vs. the straight (no angle) cable orientation.

[Sdonnel]

I had the same issue on my first FFR. I installed the Forte throttle linkage and the issue was completely gone. The amount of binding between the internal wire turned out to be the issue. You may also look at routing. Too many turns in the throttle cable will make it notchy as well.

Scott

[Rdone585]

The only thing I had success with was making sure the cable had as straight a run as possible. It winds up being in an "S" pattern as it makes it's way to the carb. Do you have anything holding it in place on the intake? If not, that might help. Also make sure the return springs are in place with good tension but not so much that they make it hard to initiate throttle action. I finally, after almost 20 years switched to the mechanical throttle assembly. Why did I wait this long, it's one of the best adds I've done. Mine was a challenge because I have the mustang pedal assembly. It was in the way for the linkage to the assembly. But after getting it to work, it was well worth every bit of effort to get it done.

[john42]

Are you running a Holley Sniper or similar setup by chance? What you're describing is a pretty common complaint. The fix recommend in the Holley forum is to extend the throttle linkage about 1/2 inch to get a bit of angle vs. the straight (no angle) cable orientation.

I'm running a Trickflow intake. I'll see if a similar mod would apply tho! Thanks!

[john42]

I'll look into the spring too! Yes, the initial force to overcome the spring tension is high.

[rthomas98]

I'll look into the spring too! Yes, the initial force to overcome the spring tension is high.

Do you have pictures of your current set-up on the throttle body? Because their are multiple things that could be causing this. Spring tension too high. Springs orientated differently. As others have said above cable orientation.

You might also want to check on how the cable is pulled at the pedal. It should be a straight in and out similar to the throttle body side. If it is getting pulled down at an angle can also create this issue.

[Geoff H]

What accelerator pedal are you using? When I used the stock mustang pedal it was an on/off switch. I switched over Russ Thompson's pedal https://breezeautomotive.com/shop/gas-pedal-kit/ and the lever point was different. Made a big difference in my application. I also dry-lubed the cable and that helped too.

[CraigS]

A cable can be made to work OK. I did that for about 10 years. Like rthomas said, my pedal initially was pulling the cable down as it came out of the firewall fitting. It had actually sawed part way through the aluminum fitting. Also look at the top portion of the pedal above the pivot. Think of an old clock where the shaft the hands attach to is analogous to the pedal pivot and your cable comes through the firewall and aims at the 12 oclock position. You want the top of the pedal to move between say 10 oclock and 2 oclock. Or 1030 and 130. You don't want it to move between 11 and 3 or 9 and 1.
https://live.staticflickr.com/65535/52147405932_5caee38731_z.jpg (https://flic.kr/p/2ns65ZJ)Pedal (https://flic.kr/p/2ns65ZJ) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr

[john42]

Thanks for all the suggestions!! I think I have it fixed. I found that the mass air flow sensor wires for the trickflow intake where getting fowled in the throttle spring. I've resolved that and it's much smoother now.

[john42]

So I’ve been futzing with this since before I posted this question. Finally, came to a WOW fixed it moment. First, aside from the jerky throttle, I’ve also not been comfortable with the location of the gas pedal. I was not able to heal-toe at all in auto-cross and the pedal was crazy close to the trans tunnel. The rubber of my shoe would pinch and get stuck between the carpet and the pedal. Fast forward to today….

I replaced the 1990 Fox donor pedal with the one from Breeze. I was able to adjust and place the pedal exactly where I wanted it and as it turns out it was the joint of the donor pedal that was the root cause of the “sticky” feel/response of the throttle. Now it is silky smooth and 1000x more comfortable for my foot and I can finally heal-toe properly.


Shout out to Breeze on this one!

[Chopper]

That Russ Thompson gas pedal is awesome. Love mine. Feels good to get it sorted I'm sure!

[rich grsc]

So I’ve been futzing with this since before I posted this question. Finally, came to a WOW fixed it moment. First, aside from the jerky throttle, I’ve also not been comfortable with the location of the gas pedal. I was not able to heal-toe at all in auto-cross and the pedal was crazy close to the trans tunnel. The rubber of my shoe would pinch and get stuck between the carpet and the pedal. Fast forward to today….

I replaced the 1990 Fox donor pedal with the one from Breeze. I was able to adjust and place the pedal exactly where I wanted it and as it turns out it was the joint of the donor pedal that was the root cause of the “sticky” feel/response of the throttle. Now it is silky smooth and 1000x more comfortable for my foot and I can finally heal-toe properly.


Shout out to Breeze on this one!
Had we know you were using the donor pedal, it would have been an easy, instant diagnosis. ON-OFF is how that thing works.:rolleyes::(. Glad you've made the change

[Jim1855]

Just something else to look at and consider. Saw this on a friend's car.
The linkage at the manifold that turned the pull direction by 90 degrees was sloppy and very poorly done. Big "lumps" in the movement, horrible initial throttle control. It was OK once past the early transition from idle to part throttle. I drove it once, didn't want too again.
Ultimately he corrected the linkage, much better now.
Jim

[Papa]

Perhaps a bit of a thread hijack, but with the new stacks setup, I'm noticing a little sticking on the throttle. I'm wondering if adding a spring on the RT pedal would be a good idea? The cable I'm using is a brand new Lokar with the black outer sheath.

[Rdone585]

Papa, I'm sure you've probably already thought of and tried this, but I would attempt to smooth it out with cable routing. Maybe even new brackets and cable retainers to ease the curves. Also make sure the engagement from the pedal through the firewall is straight. I would hesitate from using a spring on the pedal for fear that I would get tangled up in it at just the wrong time. But then, maybe I don't fully understand what you have in mind.

[Papa]

Papa, I'm sure you've probably already thought of and tried this, but I would attempt to smooth it out with cable routing. Maybe even new brackets and cable retainers to ease the curves. Also make sure the engagement from the pedal through the firewall is straight. I would hesitate from using a spring on the pedal for fear that I would get tangled up in it at just the wrong time. But then, maybe I don't fully understand what you have in mind.

Thanks. I'll create a new thread as this looks like it will deviate from what this thread topic is.