My car is a 86 T/A 305 LG4 5 speed with 230k miles on it. I have been dealing with a high idle problem for some time now. at idle it is turning around 1200rpm, I can tap the peddel and nock it down to the idle screw every time. but I have to do it every time.

looking at the carb I can see it is sticking about a 1/8 inch away from the screw, a light touch of my fingure and it will drop the rest of the way. is it somthing sticking or an adjustment?

any help is appreciated.
chuck

 

On my car, when slowing down to a stop, I have to leave the clutch engaged untill the engin slows below about 1200 RPMs. If I don't, then the Throttle Kicker Sol. stays energized and it idles at aprox 1500 RPMs. When the computer sees the RPMs below 1200, it shuts off the Kicker.

 

Sounds like the same problem! I tap the peddel and you keep the clutch engaged. now how do we make it right

Chuck

 

O.K. it's not the same problem. keeping the clutch engaged to 700 or 800 rpm and when I disengage the engine jumps back up to 1200rpm, the only way I can get it down is to tap the peddel.

help
chuck

 

IMStress- I have the same poblem as you. I was asuming I need a rebuild- but if anyone has any other ideas? '84 w/L69, 130,000 mi.

 

Your choke isn't opening all the way. Almost guaranteed. The choke linkage has what's called a "high idle" cam that raises the idle speed any time the choke is closed- even slightly. Get your car running at that high idle like when you're having the problem. Yank the air cleaner assy. Look over at the mess of linkages between the round choke element and the main body of the carb. Look for a lever with a sorta trianglular shaped head on it, made of thick metal (1/8" or so), with the head bent slightly towards the body of the carb. Push down on it. If it moves down slightly and your idle returns immediately to normal (700 or so- wnatever's normal slow idle for your engine) then this is your problem.

Now FIXING the problem is a different story. There's 3 possibilities:

1. Linkage mechanically binding or gummed up. Spray it all down with carb cleaner and see if it fixes the problem.

2. Not getting a full 12V to the choke heater. It's the single wire going to the round black choke element on the pass. side of the carb. With the engine running yank it and measure voltage between that wire and a good ground. Should be 12V or whatever your normal running voltage is (14V or so with engine running). If not- figure out why and fix it.

3. Choke element getting flaky. 200K miles is a lot of miles. Choke elements don't last forever. Replacing it is as simple as buying a new choke element kit and installing it per instructions. You can do it with the carb on the car. It's just drilling out 3 rivets, putting in the new choke element and aligning it correctly, then installing 3 self-tapping screws (provided) in place of the old rivets.

This is all diagnosable and fixable, even for a novice with limited tools.

 

First of all, thanks for the help Damon

thats cool my Akikdo instructors name is Damon.

I ran the car ideling high, visably 1/8" off the idle screw. Pushing down on the lever you discribed does nothing, it is all the way down. Power is good to the chock and it seems to be operating correctly. I disconnected the accel pump and throttle cable in case they were binding, with no effect. if I rev it up and let it go it will drop to normal idel, or if i push down on the throttle lever it will drop. the only other place I can make it drop is by pushing on a ajustment screw located under the choke "not sure what this is" I tried backing this screw off but that had no effect.

Chuck

 

Sounds like the throttle shaft/plates might be binding. Do you have a lot of freeplay in the throttle shaft? Try spraying all the linkages with WD-40, then use a pin oiler to lubricate the throttle shaft where it comes out of the carb body. Carb cleaner removes all lubrication.

 

Yank the carb and find out POSITIVELY the reason the throttle won't close against the screw. Find that out and the solution will be obvious.

 

Sure, anyone can fix it if they pull the problem off and look at it!

O.K. your right! I pulled the carb, striped it down and reset the butterfly plates. poof it's working fine now. I had it in my head that it was something external to the card body causing it. back to basics!

P.S. wile I had it apart I did the feed tube mod "drilling the 4 holes in each of the fuel feed tubes". This worked great, the bog kicking into the secondary is gone!

Thanks
Chuck

 

Good job. Glad to hear it's runnign well. I know my advice was kinda BS (or worthless irrefutable Sherlock Holmes logic that doesn't help) but sometimes it's just impossible to figure something out without having it in your hands right in front of you. I suspected we were getting to that point rather quickly so I went straight to the un-arguable. You just needed a mild bump to get you off the dime. I knew you could do it. Again, congrats.

 

Dumb as this is gonna sound, and this is 99.9% likely NOT the problem, my throttle didn't get down to the idle screw for a few days...

Turns out, there was a big heavy gob of mud on the back of the gas pedal (wtf!?)

I got it off... problem solved, lol

 

LOL I had a idle problem in my grand prix that turned out to be the carpet sliding up under the pedel. can you imagin rebuilding a carb only to find that in the end. thats why I check the forums first.

Chcuk