Swede
09-03-2012, 04:48 PM
Ok people, so after many months of frustration and pulling my hair out, I finally got to the bottom of my high idle problem.
Just to recap, my rig would idle at 1700 ish even after it was up to temperature. The only way to get it to idle normally was by physically closing the TB by hand or turning the engine off and restarting it. Sometimes if I blipped the throttle it would drop to 1000 rpm or so but climb right back up again after driving it again. I tried cleaning and testing my MAF, IAC, TPS and Throttle Body. Checked and double checked my vacuum lines. Lubed the TB linkage and rod, as well as researched until I was going cross-eyed but nothing would solve my high idle problem.
So what did I do, you ask? Well I took the TB off again and really looked closely at the linkage and the throttle valve. What I noticed was that when I held it up to a light and looked directly at the clearance between the bore and the butterfly valve itself, as I let the valve close slowly, there was contact between the two surfaces just above the rod on the TPS side before the valve was completely closed and that contact spot would move up toward the middle of the TB wall as it closed all the way.
http://img14.imageshack.us/img14/9348/20120903144609.jpg
This caused the linkage to shift about 1/16" - 1/8" away from the TPS. Everytime I opened and closed the TB the rod would shift in and out because the throttle valve was hitting the wall of the bore and shifting out. I could actually feel resistance as the valve opened and closed while it was in contact with the inside of the bore. So I tried to physically restrict the rod from sliding back toward the TPS by holding it out and when I turned it, that way it closed completely all the way around the bore with no restriction whatsoever! So all I did to prevent the rod from sliding back was put a thin washer between the spring pack and the throttle body housing. IDLES PERFECTLY EVERY TIME NOW!!! Best of all it cost me nothing to fix it.
http://img846.imageshack.us/img846/5748/20120903144541.jpg
Try it out guys and maybe it will work for you!
Just to recap, my rig would idle at 1700 ish even after it was up to temperature. The only way to get it to idle normally was by physically closing the TB by hand or turning the engine off and restarting it. Sometimes if I blipped the throttle it would drop to 1000 rpm or so but climb right back up again after driving it again. I tried cleaning and testing my MAF, IAC, TPS and Throttle Body. Checked and double checked my vacuum lines. Lubed the TB linkage and rod, as well as researched until I was going cross-eyed but nothing would solve my high idle problem.
So what did I do, you ask? Well I took the TB off again and really looked closely at the linkage and the throttle valve. What I noticed was that when I held it up to a light and looked directly at the clearance between the bore and the butterfly valve itself, as I let the valve close slowly, there was contact between the two surfaces just above the rod on the TPS side before the valve was completely closed and that contact spot would move up toward the middle of the TB wall as it closed all the way.
http://img14.imageshack.us/img14/9348/20120903144609.jpg
This caused the linkage to shift about 1/16" - 1/8" away from the TPS. Everytime I opened and closed the TB the rod would shift in and out because the throttle valve was hitting the wall of the bore and shifting out. I could actually feel resistance as the valve opened and closed while it was in contact with the inside of the bore. So I tried to physically restrict the rod from sliding back toward the TPS by holding it out and when I turned it, that way it closed completely all the way around the bore with no restriction whatsoever! So all I did to prevent the rod from sliding back was put a thin washer between the spring pack and the throttle body housing. IDLES PERFECTLY EVERY TIME NOW!!! Best of all it cost me nothing to fix it.
http://img846.imageshack.us/img846/5748/20120903144541.jpg
Try it out guys and maybe it will work for you!