Will a throttle cable stretch over time?

[67CudaBob]

67 Dart 273-2 married to a 904. Stock everything.

When I bottom out the pedal, I am only about 75% open, which is capping me out at about 65mph.

Investigating yesterday, it appears the throttle cable at some point was misrouted and was under great strain. We were able to re-route it to what I believe is correct, but am still unable to adjust to proper. I can either have about 85% pedal. Or, when we adjusted to get 100% pedal, then "something internal" would not close properly leaving a high idle (I am not a carb tech guy - so go easy on me).

My buddy says he thinks the cable stretched over time from being misrouted and under great strain. Searching threads here, I found nothing on stretched throttle cables. But at this point, we are not sure what else it could be.

Anyone with experience here who knows?

I will try to post pics today to see if anyone notices anything that is out of place.

Thank you

 

[krazykuda]

Yes, they can stretch a little over time and strain. But they can only stretch a little as they are metal which can only stretch so much.

There are two basic components in a cable. You have the conduit (the outer housing/tube) and the strand (the part that goes into the tube).

If you want to try to "tighten" it back up, you may try to crimp a fishing weight (the small round type) to the end where the pedal goes, just under the original "button" end that the throttle works off of. (You can't crimp it at the carb end, as it will interfere with the hook up to the carb). Maybe try to crimp the old round crimp on metal fishing weights on the end just before the "button) to essentially make the strand "shorter" as the car sees it. Be careful doing this as it may interfere with installing the strand into the pedal end. Maybe crimp the weight on while the cable is still installed.

The best way to fix this is to replace the old worn out cable assembly with a new one.

 

[RedFish]

I've got a chart here that shows stress limits, stretch, etc.. for a lot of cable types. Braided wire rope, spiral wounds, all different. Anyway... Your foot effort wouldn't stretch it very much at all.
Unless you bought the car new you can't be sure of stock everything. Replacement cable or change in throttle pedal assembly are my guesses. Your condition is somewhat common where a slant 6 cable is used on a V8.

 

[67CudaBob]

KK-

Good call on testing with a small lead weight at the pedal, there is just enough room there to try that. If that is it, I will go for a replacement.

If I go new, anyone know if a replacement is made for a 273-2 for my car? They certainly cannot be in demand. Maybe there is a universal? I suppose I could also post over on parts wanted and see if anyone has one laying around.

Thank you

 

[ab7fh]

On the Ford Explorers we do a "throttle cable mod" which places nylon tie wraps at the gas pedal end of the cable. The tie wraps take up the space that the cable stretch leaves, ensuring you will once again get WOT. I'm pretty sure that could be done on the A-body as well.

With the gas pedal in it's fully up position reach under and pull the throttle cable towards the rear of the car. If there is a gap, fill it with tie wraps...

On my A-body with a Holley Dominator I had to bend the gas pedal bracket slightly to get it high enough off the floor to give me WOT and that was with a fully adjustable Lokar throttle cable and Jegs, adjustable cable bracket. Sometimes you need to monkey around a bit to get it right...

 

[67Dart273]

I'm sure these cables stretch SOME but I don't see how they would ever stretch enough to get into an "80 some" percent deal. Look at your clamp setup near the carb. There's a LOT of adjustment there. It's far more likely that something has been replaced or mis-installed over the years Photos most certainly would help.

As old as all these old girls are, even the ones in the 70's and 80's, anything is possible

Start by downloading yourself a free factory service manual here:

http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617

or here

http://www.mymopar.com/index.php?pid=31

Throttle /kickdown setup is in the Torqueflite transmission section. This does not show it very well, but this clamp allows a lot of adjustment on the throttle cable. Also check that the carpet is not interfering under the pedal

 

[67CudaBob]

Red

I agree - I work in the wire rope industry, and stretching metal takes a lot of force. Knowing it was mis-routed could easily mean it is not a factory cable. What I meant to say is the motor and carb and such are stock.

 

[ab7fh]

Here's a pic of a Ford with one cable tie added:

I actually have three on mine. They do stretch after 20 years...

 

[67CudaBob]

67Dart-

I am glad you posted that pic. I have the manual. Looking at that pic, doesn't it appear that the throttle cable routes behind the kick down? My conduit is so stiff, there is no way I can get it to do that. I haven't just in front of the kick down now (which is far better than where it was).

We are clear of the carpet, and when the cable is adjusted all the way back in the bracket, I obtain WOT, but that is when the internals won't close and leaves me with high idle.

I am suspecting an improper replacement at some point as some have pointed out.

 

[67CudaBob]

ab7fh-

Awesome pic - I will try that first. Simple and free - gotta love it!

 

[Daves69]

67Dart-
We are clear of the carpet, and when the cable is adjusted all the way back in the bracket, I obtain WOT, but that is when the internals won't close and leaves me with high idle.
.

Just a thought. When you adjust the cable "conduit" back (in post #6) are you holding the throttle in the closed position? If not you need to. Then move the cable "conduit" forward .060" and tighten the nut. From there manually open the throttle and make sure it opens completely without bottoming out anywhere on the cable.

 

[66plyValiant]

ab7fh-

Awesome pic - I will try that first. Simple and free - gotta love it!

don't ad zip ties, that's a half assed fix, all mopar engines have throttle cable adjustment

with the engine running, loosen the lock nut on the throttle cable on bracket on the intake

, pull back on the cable case until the car starts to rev up a little, release it some so you get normal idle but the cable is still tight and tighten the lock bolt, confirm you have full pedal travel

if you don't check to make sure the carpet doesn't have a crease under the gas pedal, and the spring on the gas pedal isn't broke allowing the black plastic piece foot rest to flop on the metal pedal assembly