General throttle cable question

[Trstno1]

When one adjusts the throttle cable they are suppose to adjust it so the the low ide micro switch gets tripped when one lets off the gas pedal right? The other question would be I just noticed that with my gas pedal to the floor, the high idle micro switch is not even close to being tripped. This isn’t right, right?

I would think that accelerator pedal to the floor, the high idle switch should be actuated and accelerator pedal with nothing on it should actuate the low idle micro switch.

Is this right? If so, my low end is working but my high end not so much. Which leads me to believe that I’m not opening up the butterflies all the way, thus losing a little power.

Does this sound right?

[Bitsyncmaster]

Yes that is how it should work.

Maybe your pedal is somehow bent or linkage to the cable is sloppy. Also there is some adjustment with the linkage on the throttle spool.

[Trstno1]

Yes that is how it should work.

Maybe your pedal is somehow bent or linkage to the cable is sloppy. Also there is some adjustment with the linkage on the throttle spool.

ok. So just so we are on the same page here.

Is this the correct operation??

Pedal is to the floor- the throttle plates are fully open, and the full throttle micro switch is pressed?
Foot is off of the accelerator pedal- the throttle plates are fully closed and the low idle micro switch is being pressed?

In correct adjustment and operation, the throttle spool will go from the low stop to the high stop right?


Can someone post a picture of their throttle spool, throttle linkage, and throttle plate position at full throttle and at idle? I cannot seem to find any pictorial or video footage of the correct operation.

[Bitsyncmaster]

Yes your statement of operation is correct.

There is a throttle pedal stop but mine is full throttle a little before I hit that stop.

To get the maximum throw at the spool you would want the link to be at a 90 deg position at half throttle. Normally you also want a little slack in the cable at idle so you bottom out on the "curb idle screw" to set the position and not rely on the cable returning to exactly the same position each time.

[Trstno1]

Yes your statement of operation is correct.

There is a throttle pedal stop but mine is full throttle a little before I hit that stop.

To get the maximum throw at the spool you would want the link to be at a 90 deg position at half throttle. Normally you also want a little slack in the cable at idle so you bottom out on the "curb idle screw" to set the position and not rely on the cable returning to exactly the same position each time.

Man, this thing is really starting to bug me.

I took the w pipe off to see the throttle plates. I took off the throttle cable all together and adjusted the throttle linkage so that the spool fully open has the throttle plates fully open and the high idle switch engaged. And reciprocally, the spool fully closed and the throttle plates are closed and the idle micro switch is engaged. Everything goes to garbage when I attempt to hook up the throttle cable. I don't seem to have enough movement of the cable to completely open and close the throttle plates and hit the micro switches on both sides. I can either adjust it so that the spool returns fully and engages the idle micro switch when accelerator pedal is up, but doing so will not allow the throttle plates to fully open and high idle micro switch to be actuated with the pedal to the floor. Or, I can adjust it so that the high idle micro switch is engaged with pedal to the floor, but in return the spool will not return to the fully closed position actuating the idle micro switch. Does that make sense?

So the way things stand is I can either idle correctly but never get a fully opened throttle, or I can get a fully opened throttle but not be able to idle correctly with foot off of the pedal.

The end of the throttle cable is quite frayed and hard to tighten down. I am almost wondering if it is partially broken off and too short.....

Might you have a picture of what you said:

"To get the maximum throw at the spool you would want the link to be at a 90 deg position at half throttle."

I'm having a hard time visualizing that....

[Bitsyncmaster]

Sorry I was working from memory and what I said about the 90 deg is not correct. I attached a photo full open and full shut to show you where the link arm is pointed.

I don't have and idle switch or a WOT switch. My idle ECU does not need the idle switch and my wideband has it's own switch to set a richer mixture.

[DMC5180]

If the pedal is it contacting the floor stop before you reach full spool travel. It is most likely the pedal arm is bent. Not that uncommon, it can happen if the throttle cable freezes and the driver pushes hard on the pedal to free it. The arm is very small diameter round rod.

The now deceased Screaming Yellow D, suffered from this condition.

The fix is as simple as grabbing the arm and bending it backwards by pulling on it till it is even with the Brake pedal.

A couple things first though.

Where does the Pedal sit in relationship to your brake pedal? Below , even or above?



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[Trstno1]

If the pedal is it contacting the floor stop before you reach full spool travel. It is most likely the pedal arm is bent. Not that uncommon, it can happen if the throttle cable freezes and the driver pushes hard on the pedal to free it. The arm is very small diameter round rod.

The now deceased Screaming Yellow D, suffered from this condition.

The fix is as simple as grabbing the arm and bending it backwards by pulling on it till it is even with the Brake pedal.

A couple things first though.

Where does the Pedal sit in relationship to your brake pedal? Below , even or above?



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Holy cow , I never even thought about that. The pedals have never been at an even level since I’ve owned it. The accelerator pedal is far below that of the brake and clutch. So, you’re saying I should just bend it back up?

[DMC5180]

My pedal arm position at rest against the upper adjustable stop bolt.

https://uploads.tapatalk-cdn.com/20180421/5f61134a5d51f38e886ea7e94627ae28.jpg

Full throttle

https://uploads.tapatalk-cdn.com/20180421/0efce9ad00dc49d991e1f437a2b57678.jpg

Pedal position at rest

Even with brake pedal. (Skewed by photo angle)

https://uploads.tapatalk-cdn.com/20180421/a6d68c830f28f8ddf9080bb6fb516fbf.jpg


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[DMC5180]

Holy cow , I never even thought about that. The pedals have never been at an even level since I’ve owned it. The accelerator pedal is far below that of the brake and clutch. So, you’re saying I should just bend it back up?

I think before you bend it back, I would look at the upper adjustable rest stop.

Mine has approximately 1 inch of visible thread showing, or roughly 30mm from top of bolt (rest stop) to the threaded nut. If you have something close to that. Then I would say the lower arm is bent. If you have more thread exposed, it may be possible for you too screw the adjuster bolt in until the arm appears level. However, by doing this you would likely need to take up any cable slack by loosening the the cable pinch bolt on the throttle spool and pulling the the slack out, then retighten the pinch bolt.




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[Trstno1]

I think before you bend it back, I would look at the upper adjustable rest stop.

Mine has approximately 1 inch of visible thread showing, or roughly 30mm from top of bolt (rest stop) to the threaded nut. If you have something close to that. Then I would say the lower arm is bent. If you have more thread exposed, it may be possible for you too screw the adjuster bolt in until the arm appears level. However, by doing this you would likely need to take up any cable slack by loosening the the cable pinch bolt on the throttle spool and pulling the the slack out, then retighten the pinch bolt.




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Yup..the upper adjustable rest stop has exactly 1” of thread showing. So I bent the pedal back up and now I have full movement. The only issue I see now is that everything works as intended when the car is off. However when the car is running and I let off of the pedal it doesn’t quite actuate the idle micro switch. Ill mess with it a bit more to see if I can dial it in.

Thank you so much!!

[DMC5180]

You’re very welcome.

The position of the throttle spool ball stud should be very close to what you see in Dave’s first photo. From that point you can adjust the linkage ( shorter ). Before you adjust anything. Make sure the idle stop screw is not contacting the the bracket pad. This should ensure the the throttle plates are fully closed.

Once you have that then you can either adjust the linkage to remove slack (preferred) or adjust the Micro switch contact screw.


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[Bitsyncmaster]

Quite a few people have had issues with the throttle closing when the engine is running but works fine when the engine is off. The idle vacuum seems to make the closing require more spring pressure. Make sure the idle switch is adjusted so it does not stop the closing to the curb idle screw. There are some idle switches that require less pressure to operate which some owners have tried.

I found greasing spool spring also helped when I had that problem.