Idle is out of control!!!

[racerx]

Right after a spirited drive last night, the car decided that it would go ahead and idle all the way to the rev limiter....

I think it has something to do with the throttle cable or wheel getting stuck...

Or maybe the throttle spring?

Does anyone know what the heck is going on?

[racerx]

ok, i just sprayed the cable and wheel with carb cleaner and then liquid wrench...

Well, it worked ok for a few seconds. I revved it up plenty good, and then! it stuck again, this time at about 3000rpm (better than redline).

So, I got out of the car (while it was still running) and pushed the throttle wheel back, and behold, it went back down to idle.

What could be causing this? Do I need to take the wheel off and clean it?
Is there a valve inside the TB that needs cleaning?

[racerx]

ok seriously, somebody has got to have an idea...

[NXRacer]

might want to take the air cleaner off and check the carb to see if the throttle plates are getting stuck somehow. Also, try taking off the throttle cable and see if the cable is getting stuck in the 'sheath' or the carb is sticking somehow. Process of elimination. . . .

[danronian]

Sometimes the butterfiles will spin around in the carb and get stuck and that messes everything up, it usually occurs during a backfire. I am not sure if this applies to the 3g carb but it is a general carb thing.

[osmialo123]

I would recommend checking the cable. If it is getting rusty or the casing around it is cracked thats probably the cause. Also make sure the spring isn't rusty. You can also try to adjust the warm/cold idle speeds. its fairly simple. Is your carb new or getting old? Is it the 2bbl or 4bbl model as the two work differently and different things can cause the engine to rev. Also if the carb needs to be cleaned it can cause the engine to rev, cleaning it would probably be your best bet.

[accordlxi2.0]

clean the carb barrels and clean the throttle cable real good, and loosen the throttle cable nut a bit.

[A20A1]

Yeah free play is there for a reason.

[racerx]

the cable is fine. I think I'm going to just replace the throttle wheel.

[bobafett]

this happened to me when i had a "bored" throttle body, and the check engine light came on and told me i had a bad TPS....

[HondaBoy]

did you say it was reving up the to the rev limiter? didnt know any carbed models had that. lol. and its 2 bbl, not 4 bbl because the 3gee didnt have a 4bbl carb. maybe two 2 bbls. anyway, hopefully you know what your doing on your carb. dont wanna screw things up worse than they are. i'd say take the air cleaner completely off. then with the engine turned off, open and close the throttle by hand watching for things sticking. look inside the barrels to see if the butterflys close down on the throttle plate. they should close pretty easily if the springs are still springy. i dont know if a vacuum leak would cause this though, it could be possible, but for how high the idle was going by itself i dont think that would be it. i'd say keep that liquid wrench spray away from your carb though.

[racerx]

ok, here's some more observations:

If I drive gingerly, it won't stick as bad. If I mash the pedal, it will really want to rev.

Sometimes though, it'll drop down a little bit... It will stay at, oh, 3000, and then drop to 2500, as if the fast idle just turned itself off or something. I'm going to spray some carb cleaner on the vacuum lines and see if that helps.

[acranox]

could the spring be broken?
I would think that the problem would be pretty obvious if you look at the operation of the throttle cable at the carb.
Try disconnecting the cable from the carb and make sure things move properly.

[POS carb]

it happened to mine once, a screw came out of the carb and fell down the barrel and got stuck/ it wasn't letting the throttle close all the way.

make sure you weren't screwing around with the secondary vacuum, also make sure the piece that blocks the secondary from opening at part throttle isn't missing (try applying vacuum to the secondary while the pedal isn't pressed, it should not open more than a hair)

[A20A1]

oh there are some rare cases that the metal wheel on the secondary linkage that follows along the profile of the primary linkage can get stuck in the groove where the primay lets the secondary open and it will hold the primary and secondary barrels open. but I only notticed that happen after I converted to mechanical secondary... I beleive it migh just be more of a timing issue where the secondary is opening too early so there is a good amount of pressure which pinches the to linkages together near the groove.

[racerx]

ok, here's what happened. (by the way, I fixed it).

Carbon build up.

Rule #1: NEVER connect your valve breather to your CAI....

Rule #2: Don't listen to your friends. :)

Well, I never wanted to connect that valve breather in the first place. I just wanted to throw a breather filter on it and call it a day, or run a hose away from it.
But no. Since there's a little nipple on the pipe, that means you "HAVE" to connect the hose there.
Well, my valve train is a little old... ok, it sucks. So there's a lot of oil and carbon and crap coming out of the valve cover.

Where does it go? Into the carb where it builds up around the throttle plates and venturis. There was so much, the throttle plates wouldn't close all the way!

So, 1 carb rebuild kit and 2 bottles of carb cleaner later, we're good to go again.

Don't worry, the new (rebuilt) engine should be done in about a week (including head with p&p, 3-angle valve job, new springs, retainers, valves, etc...)

[A20A1]

well you can add the hose to the intake but you need to filter it.... shoot even honda put two filters in the way before it gets to the carb...