Idle does not return to normal?
Thread Starter
Racer
Joined: Mar 2005
Posts: 288
Likes: 1
From: Maple Ridge British Columbia
Idle does not return to normal?
I have a strange problem with my vette's idel. I have an 86 4+3 with 100K miles and have recently had a tune up done. Replaced dist, rotor, plugs, wires, o2 sensor, fuel filter. I also had the fuel system and throttle body cleaned with BG products. The car runs great now, pulls hard and idles fine when I start it up.
The problem is that when I come to a stop, it does not return to the 7K idle, it stays up any where from 10-14K. Now if I give the throttle a blip, it will go back to normal idle. This was only happening now and then, but now its more often than not. Anything obvious I should check?
The problem is that when I come to a stop, it does not return to the 7K idle, it stays up any where from 10-14K. Now if I give the throttle a blip, it will go back to normal idle. This was only happening now and then, but now its more often than not. Anything obvious I should check?
Instructor
Joined: Jan 2004
Posts: 178
Likes: 3
From: Evansville IN
Check for slop in the linkage going into the throttle body. I would bet your problem is the hole in the throttle body where the shaft goes is ovalized and causes it to hang open. I bought a rebuilt unit from a Dave Koldos that works great and got rid of the sticking throttle. He uses bearings in the shaft so it is better than buying a new one. He also bores it to 52 mm as an added plus. Good luck Rich
Race Director
Joined: Dec 2004
Posts: 15,009
Likes: 2
First thing I would do is start her up, and pull one cable at a time from the throttle arm. There are three of them, at least there is on my 85 4+3. Throttle, cruise control and another(don't remember right off hand what it is). Bring the revs up and see if it comes down to normal idle after pulling each one.
In my case, it was the cruise cable. Of course I found this out after I had completely disassembled the throttle body.
But, it needed cleaning anyway.
Check all of your cables/cable housings for wear first, before you spend any money. Especially where they mount to something.
In my case, it was the cruise cable. Of course I found this out after I had completely disassembled the throttle body.
But, it needed cleaning anyway. Check all of your cables/cable housings for wear first, before you spend any money. Especially where they mount to something.
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
Originally Posted by richdwyer
Check for slop in the linkage going into the throttle body. I would bet your problem is the hole in the throttle body where the shaft goes is ovalized and causes it to hang open. I bought a rebuilt unit from a Dave Koldos that works great and got rid of the sticking throttle. He uses bearings in the shaft so it is better than buying a new one. He also bores it to 52 mm as an added plus. Good luck Rich
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
I had that problem too - it was the worn throttlebody were the throttle shaft rotates - there is amazing airflow on the throttle blades at idle and they jam without fully returning.
I have a recon TB by David Koldos actually in the post to me at this moment. For 9 months I have been removing the rubber air hose and squirting grease with a fine nozzle into all the openings that the throttle shaft goes into - the throttle becomes smooth again for a few weeks. It's temporary cure, lasts 9 -16 weeks and then gets stiff again - that proved what the problem was and D Koldos has the answer -better than new !!!!!!
S'nut
I have a recon TB by David Koldos actually in the post to me at this moment. For 9 months I have been removing the rubber air hose and squirting grease with a fine nozzle into all the openings that the throttle shaft goes into - the throttle becomes smooth again for a few weeks. It's temporary cure, lasts 9 -16 weeks and then gets stiff again - that proved what the problem was and D Koldos has the answer -better than new !!!!!!
S'nut
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Team Owner
Joined: Jan 2003
Posts: 20,304
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From: Summerland B.C. Canada
Originally Posted by richdwyer
Check for slop in the linkage going into the throttle body. I would bet your problem is the hole in the throttle body where the shaft goes is ovalized and causes it to hang open. I bought a rebuilt unit from a Dave Koldos that works great and got rid of the sticking throttle. He uses bearings in the shaft so it is better than buying a new one. He also bores it to 52 mm as an added plus. Good luck Rich
Check the drivers side of the throttle shaft. I'll bet you can move the shaft back and forth in the bore.
Thread Starter
Racer
Joined: Mar 2005
Posts: 288
Likes: 1
From: Maple Ridge British Columbia
Wow, great responses and quick too! I knid of suspected it might be the TB, but they cost alot so I was making sure there wasn't an easier fix. I will check the cables to see if they are sticking as that makes sense. If that's not it, looks like a new TB for me. BTW, how do I contact Dave?
Team Owner
Joined: Jan 2003
Posts: 20,304
Likes: 240
From: Summerland B.C. Canada
Thread Starter
Racer
Joined: Mar 2005
Posts: 288
Likes: 1
From: Maple Ridge British Columbia
Took all the advice from this thread and applied it. Checked the cables and they seemed OK. Then I removed the air inlet hose to the TB and looked inside. YUCK! It was coated with carbon. Apparently the shop where I had the tune up done had cleaned the fuel system with BG products, but didn't clean the TB. An hour later after a thorough cleaning with the TB still on the car and some TB cleaner sprayed in and all was good. It returns to normal idle now and runs smoother to boot! When I next get time, I'll take the TB off the car and really give it a good cleaning. Thanks to all for the good advice.
