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Throttle cable sticking

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My throttle had been sticking at about 1500 rpm until i press the gas pedal sharply, then it goes back down to normal idle rpms. I recently replaced the throttle cable and made it run directly from the firewall to the carb, instead of in a loop as it was before, and the problem was much worse, until I adjusted the part where the cable cover mounts on the carb in order to make the curves less drastic. It seems to be a bit better now, but still sticks sometimes until I blip the throttle.



If I open the throttle manually on the carb, it goes back to idle no problem.. so its not the springs, or the carb in any way.


The spring on the gas pedal feels a bit weak, but I'm not sure if that could make this happen.


I am thinking that the cable must be sticking inside the cable cover somehow, but I have lubricated it with LDL dry lube spray very well. Should I use a different lube?


Has anyone else had this problem? 


PS. I have an auto trans, and the cable from the trans to the carb is engaged anytime the throttle is opened. I know it should slide and only engage when the throttle is wide open, but I did not have a problem with it before. Could the tension from this cable help the throttle close?

Edited by Atozone Tonine
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Does it physically feel like something is blocking the return, or is it just slow?


Try and get the cable level coming out of the firewall to the carb, and as for inside the firewall a nice slight curve from the gas pedal will help.


Another thing you can do is get a stiffer spring and bracket. The bracket has a small hole on the end and a big hole for the bolt on your intake manifold. It is L ShapedThis should fix all your problems

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Be careful, I had my throttle stick wide open on the highway passing someone.  My passenger and I about crapped our pants, not fun in a 9 second car floored, you have little time to react!  I pushed her in nuetral and turned off the key, coasted to the side of the road.  The look on my passengers face...ouch!

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Could be unrelated to the cable.  Might be part of the factory pivot that is usually utilized.   I had a similar problem on my one Z. The factory pivot on the firewall, the rod inside of it was corroded and had somewhat of a flat spot on it.  Sat with some emory cloth and greased it good afterwards and things are much happier.  I'm not a V8 swap but my problem was very similar to yours.

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If the cable has frayed inside of the sheath lube will not help.  Find out why the cable is fraying and replace the cable. The cable may be binding and rubbing on the sheath end which will cause the cable to wear braking the cable strands.  Eventually the broken cable strands will catch and bind the cable inside the sheath. 


Is the cable lined up with the gas pedal attachment point?  This happened on my first 240Z project which is why I now connect a short cable to the factory bell crank as shown in the picture above.


Also, when you post provide more information: year, model of car, engine and trans used.

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  • 2 weeks later...

I am a firm believer in the KISS (Keep It Simple Stupid) method when it comes to engineering changes and a sticking throttle is something that you don't want to deal with.  Even though I have a Tri-Power setup on my car you can very easily do the same basic installation.  Buy yourself the shortest Lokar universal throttle cable and appropriate carb bracket.  http://lokar.com/product-pgs/throttlecables-kickdowns/tc-kd-pgs/throttle-cables.html 


Depending on your carb you may want to buy the whole kit which includes the highly recommended dual return springs.  Don't worry about the length when you buy it is as you will end up cutting it to the correct length. 


Next, remove all the old throttle parts including the throttle bracket and bell-crank.  

Install the new Lokar throttle bracket on (or under) the carb depending which one you purchased.  Remove the cable from inside the housing and the measure and cut the housing to the right length.  Keep the bends wide and remember that the engine will rock on its mounts so do not make it to short.  Remove the clevis from the gas pedal end of the cable and reinsert the cable in the housing.  Now insert the new cable through the original hole in the firewall.  Hook the end of the cable onto the stock pedal by inserting it through the original slit.   

Next mount the other end of the housing onto the carb throttle bracket. Measure and cut the cable and install the end and ball on the carb. Be sure to install the redundant set of springs.

I think you will find that the throttle will operate very smoothly and you will no longer have a problem with sticking. I have been running mine like this for over ten years and never had a problem.



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